How to Take Smart Notes

If you’re someone who publishes original insights for a living—like a non-fiction writer or an academic—how can you make your writing process as efficient as possible? In How to Take Smart Notes, researcher Sönke Ahrens presents a method for doing so: The slip-box system is a method of taking notes and organizing them that fosters the creation and publication of original ideas. In the original version of the system, writers took notes on index cards and organized them in a “slip-box,” or cabinet; today, a digital version is more common.

Ahrens argues that since this slip-box system is specifically designed to help you both have and share original insights—and make the writing process easier overall—it has several benefits over the traditional writing process: For example, using it will make you more efficient and lead to more creative insights.

(Shortform note: Most English-speaking users of the slip-box system refer to it as the Zettelkasten, its original German name. But Ahrens uses the term “slip-box system” because it’s the direct translation of Zettelkasten, and because he uses the term Zettelkasten to refer to a specific computer program by that name. To avoid confusion with this computer program, this guide will also use the term “the slip-box system.”)

In this guide, we’ll first discuss the origins of the slip-box system: Who invented it, and why have you (probably) never heard of it before? Then, we’ll preview how to use the system and examine whether you should try an analog or digital version. Finally, we’ll discuss the specific features of the slip-box system that make it an improvement on traditional productivity systems. Along the way, we’ll examine how Ahrens’s techniques compare with the advice of other productivity experts.

The Origins of the Slip-Box System

Ahrens explains that the slip-box system was invented by Niklas Luhmann, an incredibly productive German sociologist. Not only did Luhmann publish nearly 60 books within his lifetime, he also has several posthumously-published books to his name—thanks to the ideas he collected within his slip-box.

(Shortform note: Writers before Luhmann, who was born in 1927, also used note-taking systems similar to the slip-box system. Notably, in 1921’s The Intellectual Life, French philosopher Antonin Sertillanges also describes a note-taking system where you take notes on uniform sheets of paper, label them, and relate them to each other with a classification system.)

Luhmann was vocal about how the slip-box system helped his productivity. However, the system only gained popularity within a small niche, which Ahrens attributes to two main reasons. The first is primarily linguistic: Since Luhmann was German, most of the publicly available information about his system was in German.

(Shortform note: If you do speak German, reviewing the digitized version of Luhmann’s slip-box in conjunction with his published works may help you gain a more thorough understanding of his system.)

Second, as Ahrens argues, people misunderstood the system: They focused solely on the slip-box and not the overall workflow dictated by the slip-box. Since they didn’t understand how to use the slip-box system to its full advantage, they were never as productive as promised—and the system never gained the popularity it deserved.

(Shortform note: It’s possible people haven’t focused on the workflow because it’s hard to see. Many modern users, notably researcher Andy Matuschak, have published their slip-boxes online. However, since they don’t publish the drafts of their publications, you can’t see exactly how the notes within the slip-box turn into a publishable manuscript—so it’s not as easy to understand how that part of the process works.)

How to Use the Slip-Box System

If the slip-box system is only effective when you know how to use it, as Ahrens contends, you must learn how to properly use it. In this section, you’ll learn the specific steps Ahrens outlines to effectively use the slip-box system to create a publishable manuscript.

Step 1: Take Notes

Specifically, Ahrens recommends taking three types of notes: temporary notes, literature notes, and evergreen notes.

(Shortform note: Users of the slip-box system use several different terms to refer to these three types of notes; for example, Matuschak popularized the term “evergreen notes” and occasionally calls temporary notes “transient notes.” However, the term “literature note” is common—both Matuschak and Ahrens use it exclusively.)

1. Create temporary notes, which Ahrens calls “fleeting notes.” Most of us have random ideas as we go about our day. Jot these down so you don’t forget them, and put them all in one place—an in-tray, or what Ahrens calls an “inbox.”

(Shortform note: To write these as quickly as possible, use techniques to make them more concise—like by picking constructions that contain fewer words.)

2. Create literature notes. Always read with a pen—and whenever you come across interesting, potentially useful ideas, create literature notes. Using full sentences, summarize the text in your own words, making sure that you only include one idea per note. In each note, include information about the source material (like the book’s author, the year it was published, and the page number on which you found the idea). Place these literature notes in your in-tray.

(Shortform note: Like Ahrens, Matuschak suggests that writing literature notes is helpful because it forces you to engage with what you’ve read, but he adds that there are other methods of doing so: For example, some of the best readers he knows engage with literature by reading with a purpose or incorporating the ideas they read about into creative projects.)

3. Create evergreen notes, which Ahrens calls “permanent notes,” by combining your other notes. Each day, go over the notes in your in-tray and any notes you’ve already collected in your slip-box. As you do so, think to yourself: How do these ideas compare with and connect to each other? When you have an original thought about these connections, create a new note—ensuring that each original idea has its own note. Use full sentences, be as clear and concise as possible, and include citations.

This evergreen note should stand on its own; you shouldn’t have to refer to other material to understand it. For example, if you write, “Abraham Lincoln freed the slaves with the Emancipation Proclamation,” this note should include basic details of the Emancipation Proclamation but not a thorough analysis of its contents. Once you’ve encapsulated the ideas from your temporary notes into a permanent note, you can throw the temporary note away.

(Shortform note: Although your evergreen notes should contain only one concept, Matuschak urges you to “capture the entirety” of that concept: He warns that evergreen notes that are too narrow will make seeing useful connections more difficult because you’ll have ever-smaller links between notes; evergreen notes that are too broad will do the same because you’ll have too many links to the same note—making those connections unclear. For example, “Abraham Lincoln wrote the Emancipation Proclamation” is too narrow because it doesn’t provide useful context; “Abraham Lincoln freed the slaves” is too broad because it has too many possible meanings.)

Step 2: File Notes

Now that you have notes, it’s time to organize them in one of two places: a reference system or your slip-box.

1. File your literature notes in one place that’s separate from your slip-box, like a shoebox: Ahrens refers to this place as your “reference system.” When you file your notes, include the bibliographic information of each source. If you have three literature notes about one book, you’ll file those notes with a fourth note including all the book’s bibliographic information—anything you might need to include in your final published work.

(Shortform note: Despite calling the place you store your literature notes a “reference system,” Ahrens doesn’t present details as to why it’s a system and not merely a collection of references. It’s possible that Ahrens doesn’t provide further details on how this system might work because, as we’ll see later, Ahrens believes that a digital reference system is best—and digital systems all work slightly differently depending on which software you use.)

2. File your evergreen notes into your slip-box. To do so effectively, use the following system.

If your new note connects strongly to an old note—like if it supports an argument—file the new note behind that note. Otherwise, file it behind the most recent note.

Then, rummage through your slip-box and look for weaker or less obvious connections between notes you already have and your new notes. If you find any, create links between those notes. (For example, if Note #1 and Note #55 are connected, on Note #1, write down that it’s connected to Note #55, and on Note #55, write down that it’s connected to Note #1.)

(Shortform note: Matuschak advises avoiding the temptation to decide how you’ll link your notes before you develop your slip-box. He argues that if you try to force your ideas to connect in predetermined ways, you won’t be able to connect various nuances between the ideas; worse, you may not recognize a new subtopic (a series of connected notes) because it doesn’t fit into the structure you already have.)

Step 3: Link Notes to Your Index

Once you have notes in your slip-box, the next step is to link them to your index. This is any document with a list of topics with references to the notes on which those topics are mentioned. You use it to navigate the collection of notes in your slip-box so that you can find the right idea when you need it. You can link your evergreen notes to your index in one of two ways.

1. Create a new index entry whenever you notice that several evergreen notes in your slip-box all revolve around a single topic. This will consist of a keyword and the few notes most relevant to that key word. Customize these keywords so they make sense to you and help you think: For example, a food writer with Note #30 that says “The best honey comes from Australia” might file that under the keywords “ingredient origins – honey.” An economist with that same note might file it under “beekeeping industry.”

(Shortform note: Similarly, Matuschak urges you to write your evergreen notes for your own eyes; they only have to make sense to you. Some people try to write evergreen notes as if they’ll publish them in an effort to save working time down the road—but doing this risks making the task so difficult that you never write them at all.)

2. Alternatively, link your evergreen note to an existing note (that’s listed in the index) instead of to the index itself. For example, if Note #31 reads, “Australian honey is very flowery,” you could link it to Note #30 using the method described in Step 5. Since Note #30 is still in the index, this technique ensures that you can still find Note #31—but it doesn’t overcrowd your index.

Potential Pitfalls of Ahrens’s Index

Ahrens’s index differs from traditional indexes: It’s designed to help you find the high-level topics within your slip-box, whereas a traditional index would help you find every idea within your slip-box. As discussed, this is a feature, not a bug. But it may be frustrating if you’re looking for a specific note—a problem you can see firsthand if you go through Matuschak’s online slip-box.

Matuschak’s slip-box doesn’t have an index per sé; rather, he has a page that lists what he’s currently working on and notes that act like index entries. For example, one note titled “Evergreen Notes” lists a brief explanation of evergreen notes and then links to several related notes. You can learn about his ideas as you organically follow links. However, if you, for example, close the system and return, you can only return to a specific note if you remember how you linked to it originally. This is an issue that could also arise if you’re looking for a note not linked to the index in Ahrens’s version of the slip-box.

Step 4: Develop Your Ideas

Now that you have notes in your slip-box, you can use those notes to develop your ideas further. To do so, Ahrens recommends the following steps.

1. Review the notes in your slip-box and continue researching based on the questions that naturally come up: Ahrens argues that, as you create and regularly review several evergreen notes on similar topics, you’ll inevitably discover new threads of information you’ll want to follow. For example, if you’re a food writer researching Australian honey, one question that you may have—and should research—is what foods pair well with that honey.

2. Once you’ve created several notes, Ahrens argues, you’ll have enough notes to know what you want to write about. When this occurs, pull out all the notes in your slip-box related to that topic. Rearrange them in a logical way: Ahrens contends that since all these notes are your own ideas, doing so will naturally reveal some form of argument. Critically analyze this argument: Does it still have significant gaps? How can it be stronger? Use the answers to inform further research. Eventually, when you pull out these notes, you’ll have the outline of a paper.

What to Do When You’re Stuck

In the process of developing your ideas, you may get stuck. One way this can happen is if a question arises that you’re not immediately able to research, or you have a half-formed idea that seems interesting but requires further thought. In this case, Matuschak recommends writing this question or idea as a prompt and placing it into your in-tray; this gives your brain time to work on the issue but also ensures you don’t forget it.

You may also get stuck because you’re unable to pinpoint issues or gaps in your argument. This may be a symptom of an inability to criticize yourself: You may view criticizing what your mind created as a form of self-criticism. To overcome this, recognize that self-criticism can protect you in the long run: In How to Stop Worrying and Start Living, motivational speaker Dale Carnegie notes that criticizing yourself teaches you that criticism can be helpful and prevents you from having emotionally charged reactions to criticism from others.

Step 5: Write, Revise, and Publish

Once you have a de-facto outline, you can move on to the final steps. Turn your ideas into publishable form with the following steps.

1. Write a rough draft based on the notes you pulled out previously. Don’t feel married to the structure you laid out: As we’ll describe in further detail, you think as you write, so your ideas may change as you write your draft. Your notes are meant to help you develop your argument—they don’t necessarily have to be the argument.

(Shortform note: In On Writing, author Stephen King also recommends prioritizing your own thought process as you write, and he advises writing a rough draft without help or advice from anyone else. He adds that you should write as quickly as you comfortably can to keep your enthusiasm high.)

2. Revise your manuscript—repeating Steps 1-9 as necessary—then edit and publish it. Once this is done, return any notes you’ve removed to their respective homes: Literature notes should live in the reference system, while evergreen notes live in the slip-box.

(Shortform note: If you find returning notes to their respective homes tedious, you may put it off—but this is an essential part of the process. For example, if your notes aren’t where your index says they’ll be, you can’t use the slip-box effectively—which ruins the point of the whole system. One cleaning blogger contends that your laundry isn’t done until it’s put away; similarly, viewing returning notes as a non-negotiable step may encourage you to return them and prevent potential issues.)

Paper Versus Digital: Which Is Better?

Now that we’ve covered how the slip-box works, we’ll delve a little deeper into its format. While Luhmann used an analog system, Ahrens recommends a digital one. In this section, we’ll first discuss why Ahrens prefers the digital version of the slip-box. Then, we’ll discuss why you might want an analog version anyway—and what you’ll need to keep in mind if you do. Finally, we’ll explain why you should have a digital version of the reference system—no matter which slip-box version you pick.

Ahrens recommends having a digital system because it’s generally more efficient. You can access a digital slip-box anywhere; you can only access a physical slip-box if you’re standing next to it. If you go the digital route, Ahrens recommends Daniel Lüdecke’s Zettelkasten: It’s free, user-friendly, and works across multiple platforms.

However, using an analog system has undeniable benefits. Writing temporary notes on paper is generally the most efficient and portable method. Also, if you write them all in the same notebook, it’s easy to know where you’ve collected all your notes so that you can go through them at the end of the day.

(Shortform note: There are several different ways to set up your digital slip-box system. For example, many users set up slip-boxes in Obsidian. You might also consider digitizing only part of your slip-box system: For example, if you, like 81% of Americans, already own a smartphone, writing temporary notes in a notes app may be easier than lugging around an extra notebook. Alternatively, you might start with an analog system then move on to a digital system, as some users recommend: They explain that while digital slip-box systems are more efficient, starting with an analog system helps you learn the fundamentals.)

Similarly, one study suggests that handwriting improves your understanding of what you’re writing—so when creating literature notes, handwriting may help you clarify your understanding of the text.

(Shortform note: In contrast, a 2019 study suggests that handwriting doesn’t have such drastic effects: Test-takers who took handwritten notes didn’t perform significantly better than those who took digital notes.)

If you go the analog route, Ahrens recommends using A6 cards for each literature and evergreen note you create. You’ll also need a place to store your notes. Luhmann used a card catalog cabinet, but something as simple as a shoebox will also work.

(Shortform note: Other users of the system recommend changing your card size based on the size of your storage space, noting that A6 cards work best with a smaller box.)

Whether you use a digital or a physical version of the slip-box itself, Ahrens urges you to keep your reference system at least partly digital: Even if you create your literature notes by hand, you should have their bibliographic information in a digital format because most academics and nonfiction writers draft their work on a computer. By using plugins like Zotero, you can easily collect bibliographical information with just a few clicks. Zotero also integrates with several word processing tools, like Microsoft Word, which can make tracking and editing citations within your final work much easier.

(Shortform note: On Ahrens’s website, he recommends other digital reference systems you can use—namely Endnote, Mendeley, and Citavi—but explains that he prefers Zotero because it’s an open-source program that is continually being updated. However, not everybody likes digital: One slip-box system user worried that using a digital system would make collecting references too easy and thus discourage her from actually reviewing those references, so she used an analog system instead.)

Why the Slip-Box System Is Superior

You’ve now learned how to use the slip-box system, but why should you? In this section, we’ll dive into five specific features of the slip-box system that Ahrens argues make it superior to traditional methods.

#1: The Slip-Box System Requires You to Write at Every Stage of the Creative Process

Ahrens contends that people who write using the traditional note-taking process are intimidated by the blank screen because that’s the first time they think critically about their argument. As Ahrens points out, traditional note-taking methods focus on capturing others’ ideas instead of thinking extensively about them. So even if you’ve taken lots of notes by the time you sit down to write, you still haven’t thought about or developed your argument. You only do that when you sit in front of your blank screen—and that’s what intimidates you, not the writing itself.

(Shortform note: As one writer points out, the blank screen may also terrify you because you’re afraid your writing will be terrible—in other words, that you’ll fail. However, in The Magic of Thinking Big, David J. Schwartz contends that you can destroy this fear by acting—in other words, by writing anyway.)

In contrast, Ahrens argues that by making you write at every stage, the slip-box system moves this thinking work far earlier in the process—so by the time you face the blank screen, you’ve already thought extensively about what you’re going to say and no longer feel intimidated by it.

(Shortform note: Some critics contend that Ahrens overstates how easy writing a manuscript will be if you use the slip-box system. In fact, they argue that How to Take Smart Notes itself demonstrates the slip-box system’s pitfalls, describing the book as weakly written due to its repetitiveness and misrepresentation of its research.)

Ahrens contends that the process of externalizing your thoughts via writing facilitates critical thinking and ultimately results in better ideas for three main reasons.

1. You think as you write—so writing helps you think more deeply about and develop your ideas. For example, writing a literature note forces you to think critically about an author’s argument because you have to restate their ideas in your own words.

(Shortform note: Writing may also help you think more clearly because it’s something you do alone: German philosopher Arthur Schopenhauer argued that you don’t have to think while reading because the author is doing the thinking work for you. In contrast, you can only listen to your thoughts when you write.)

2. Writing your thoughts down frees up brainpower to focus on other ideas. As Ahrens explains, we have a finite amount of brainpower available for focusing on things. Moreover, even if you deliberately stop focusing on something, it still takes up some brainpower. This is because of the Zeigarnik effect: Your brain will work on unfinished problems until it’s done. But your brain treats the process of writing as a method of finishing a task—so if you write your thoughts down, your brain will regard the task as finished, so it will stop focusing on it and free up brainpower for what you need to focus on.

(Shortform note: Writing your thoughts down may not free as much brainpower as Ahrens claims: Most modern psychology books don’t mention the Zeigarnik effect because researchers haven’t been able to replicate it reliably.)

3. By converting your thoughts into a physical format, you gain the physical distance necessary to critically analyze them. According to Ahrens, your brain is great at picking up on patterns and contradictions visually—so when you look at your thoughts, you’re more likely to trigger an original insight. For example, you might notice that you contradict yourself in two evergreen notes and create a third note resolving that contradiction.

(Shortform note: Adding visual representations, such as diagrams, to your notes may further enhance this ability: Our brains process visuals 60,000 times faster than text.)

In this way, you circumvent your brain’s tendency to work in heuristics, or mental shortcuts: Writing your thoughts down forces you to clearly explain how you reached your conclusion and prevents you from jumping to them.

(Shortform note: We continue working in heuristics even after we learn how they affect us—which supports Ahrens’s contention that we need to write our thoughts down every time, even if we’re aware of the risk of jumping to conclusions.)

#2: The Slip-Box Method Follows a Bottom-Up Approach

Ahrens contends that most writers use a top-down method when working with their manuscripts. Normally, you read a little, come up with an original thesis, do further research on your thesis, then write your paper. In other words, you create ideas to support your existing thesis rather than developing a thesis that encompasses your original ideas.

(Shortform note: The top-down method that Ahrens contends most writers use may be culturally influenced. In The Culture Map, cultural communications expert Erin Meyer explains that some Western cultures think theoretically, or top-down: They’ll first formulate a general hypothesis from which they deduce a conclusion. Writers in these cultures might be more prone to the top-down approach Ahrens advises against than writers from cultures that encourage looking at the data first before drawing conclusions.)

This top-down method works in theory. But in practice, Ahrens argues, it has three main issues—all of which you can avoid by using the bottom-up approach of the slip-box system.

1. You’ll Struggle to Find Source Material

Ahrens contends that if you research after you come up with a thesis in the top-down approach, you may be unable to find sufficient source material on the topic you’ve chosen. This causes frustration and, if you’ve begun researching too close to your deadline, panic.

(Shortform note: You may also struggle to source material on your chosen topic if you’re not looking in the right places. Studies note that academics prefer to research via the internet —but using your library may provide higher-quality sources.)

But if you use the slip-box system, you never lack source material on your chosen topic. In this system, you’re not researching to prove a thesis but to grow your slip-box—in other words, to increase the number of original ideas you have. You then develop your thesis based on the ideas you collected in these notes. As a result, you can only work on a thesis that has sufficient source material to support it; if the sources didn’t exist, you’d never have enough notes on the topic in your slip-box to prompt an original idea for a paper.

(Shortform note: Depending on your field, developing a thesis from your slip-box may not ensure that you have sufficient source material on your slip-box. For example, a single slip-box note could prompt a scientist to ask a new research question—but if that research doesn’t yet exist, that scientist would be stuck unless they did the research themselves.)

2. You’ll Fall Victim to Confirmation Bias

Ahrens argues that using the top-down approach makes you especially prone to confirmation bias—a human tendency to seek out information that supports our existing views. As Ahrens points out, if you already have a hypothesis when you start researching, you naturally pay more attention to information that supports your hypothesis than information that contradicts it. But if you ignore contradictory information, your argument won’t become as strong as it could be—and you might miss out on the opportunity to have a truly original insight. By using the slip-box system, you avoid or mitigate these risks. Since you don’t start with an idea you’re trying to prove, you’re more open to disparate views and less likely to be biased.

(Shortform note: If you’ve spent a lot of time on an idea, you may also ignore evidence against it because you’ve grown personally attached to it. If this is the case, consider pausing when you encounter a new idea that casts doubts on your original hypothesis: Taking a step back could help you recognize and work through any defensiveness that might arise so that you can rationally evaluate the idea. The slip-box system builds in time for this pause: Writing up a literature note takes time, which will help you view the idea more objectively.)

3. You’ll Grow Bored With Your Work

Ahrens argues that if you use the top-down approach, you risk growing bored with your work. This can happen in two ways—both of which you can combat by using the slip-box system.

First, you may grow bored with your thesis. This can happen if, while researching your already-developed thesis, you gain a new insight that counters or significantly alters your thesis—or even leads you in an entirely new direction. You then face a dilemma: Do you switch tracks and throw away all the work you’ve done so far, or do you continue with your current project—even though you’re no longer fully devoted to it?

(Shortform note: The sunk-cost fallacy suggests that you’ll continue with your project. In Ego is the Enemy, philosopher Ryan Holiday explains that when you’ve invested time, energy, and money (sunk costs) into a project that you later realize will fail, instead of admitting that those costs are irretrievable, you’re more likely to continue to work on the project trying to make those costs mean something.)

But, Ahrens contends, if you use the slip-box system, you never face this dilemma. In the slip-box system, your thesis stems from ideas you’ve gathered in the slip-box. This guarantees that 1) it’s on a topic you’re interested in—since the slip-box contains only notes on topics that intrigue you—and 2) that it’s something you’ve thought through—since an idea only gains traction in the slip-box if you’ve thought it through significantly. As such, you’re less likely to change your mind about or lose interest in your writing halfway through your project.

(Shortform note: You may still face this dilemma if you use the slip-box but have to submit an early outline: Letting ideas arise naturally in the slip-box requires time, and if you don’t have a good idea by the time your outline is due, you’ll be forced to use the top-down approach. So if you regularly work on manuscripts that require you to submit an outline, start collecting notes in your slip-box as early as possible.)

Second, you may grow bored of working on the same piece since you’re likely working on only one manuscript at a time. Using the slip-box system reduces this possibility because you’re constantly working on multiple projects: You’re developing the slip-box with an eye for creating notes that connect in disparate ways instead of focusing your research on a specific argument. When you can work on multiple projects at once, you’re less likely to feel bored with a particular topic—and if you do, you have something else to work on.

(Shortform note: Working on multiple projects has several benefits: For example, some writers find that if they take a break from one manuscript for a few days to work on a different project, they have fresher ideas when they return to it. However, if you must work on one manuscript, try techniques to combat the boredom—like challenging yourself to write 1,000 words in an hour.)

#3: The Slip-Box System Clearly Breaks Down Your Writing Workflow

Another reason the slip-box system is superior is that it improves your overall workflow. Ahrens contends that traditionally, people collect a mishmash of reading and note-taking methods to help with their writing. But since these tools are designed to improve one step of the writing process and not the overall workflow, they actually slow you down. For example, you might use highlighting as a method to mark a useful idea in a book—but without a reference management method, you won’t be able to remember where that idea is in the book when you want to use it in your paper.

In contrast, Ahrens notes, the slip-box system breaks down your entire writing workflow, from researching to writing a paper, into the clear, logical steps we discussed previously. Since you use only one system throughout, using it speeds up your writing process. For example, you never have to remember where you highlighted an idea; you just review your literature notes.

(Shortform note: Some writers combat the potential pitfalls of using multiple reading and note-taking methods by using a single technique to manage their entire writing workflow. Notably, academic writers often develop a dedicated bullet journal for particular manuscripts. A bullet journal, as Ryder Carroll explains in The Bullet Journal Method, is a single-notebook system designed to add structure to your life, but these writers adapt it to organize the process of writing a paper. For example, they might write down the names of the documents in which they’ve written ideas, note the titles of particularly useful reference materials, and brainstorm potential research questions.)

#4: The Slip-Box System Provides Regular Feedback

Another benefit of breaking down your writing workflow, Ahrens argues, is that doing so provides regular feedback. Ahrens contends that in traditional academic writing methods, you don’t gain regular feedback. For example, you might jot down an idea you’ve learned from a book—but you don’t learn whether it’s useful until you try to include it in your paper several steps later.

In contrast, Ahrens argues that when you use the slip-box system, you gain regular, immediate feedback at each stage of the process. For example, by filing evergreen notes in your slip-box, you immediately learn whether a note is valuable: A note you can logically file behind another note and that connects to several other notes within the slip-box is probably a better idea than a note you find only a few connections to.

How to Get the Most Useful Feedback

Some methods used in academic writing do provide feedback; it just might not be useful feedback—which is why the slip-box system may be more effective. For example, you read a book to learn useful ideas from it. To do so, you might use the note-taking technique memory expert Jim Kwik recommends in Limitless: Specify your goal for your reading session, filter out any information irrelevant to that goal, then review your notes when you’ve completed them in order to make sure they’re as clear as possible. By making you review your notes, this technique provides feedback on whether you’ve understood the idea; but since you also need to know whether the idea is useful, it’s not as useful as the slip-box system.

By providing regular feedback, Ahrens argues, the slip-box system provides three benefits that traditional academic writing methods don’t.

1. The Slip-Box System Makes the Writing Process More Efficient

As Ahrens notes, in the traditional method, you might try to write about an idea you highlighted in a book—only to realize that you don’t understand the idea well and thus interrupt your writing to review the idea. Using the slip-box system provides this feedback earlier and thus avoids such interruptions. If you can’t clearly and concisely summarize an author’s idea in your own words in a literature note, this is feedback that you don’t understand the idea well—and prompts you to clarify your understanding of the idea when you’re taking notes instead of when you’re writing a draft.

(Shortform note: While non-fiction writers don’t generally get feedback from themselves at the note-taking stage, there are several techniques they use to get feedback from others before writing a final draft of their paper. Notably, university students are often encouraged to talk to their teachers or visit university-sponsored writing centers at each stage of the writing process so that they can receive feedback on their ideas, outlines, and drafts.)

2. The Slip-Box System Improves Your Skills

Specifically, Ahrens contends that using the slip-box system improves each skill necessary to write your paper—namely writing, reading, and thinking. Ahrens believes that deliberate practice is essential to improving any skill, and he believes that each step of the slip-box system is a form of deliberate practice. This is because 1) you receive immediate feedback regarding how good you are at each step and 2) you approach every step with a specific goal—for example, your goal when reading a book is to create literature notes that capture its most important ideas. Since each step is an opportunity to deliberately practice some skill, Ahrens argues, using the slip-box system makes you a better reader, writer, and thinker.

Why the Slip-Box System Doesn’t Promote Deliberate Practice

Ahrens never explicitly defines deliberate practice—perhaps because, upon further examination, the slip-box system does not constitute a form of deliberate practice.

In Peak, psychologist Anders Ericsson, who coined the term, explains that deliberate practice is a way of practicing a skill to build your potential, and he contends that it has four main features: It’s competitive, requires maximal effort, involves repeating time-tested skills, and can be measured objectively.

Non-fiction writing is a competitive field that requires maximal effort. It also involves repeating time-tested skills—experts throughout the ages have read, thought, and written—which is likely why Ahrens believes that the fact that you approach every step with a specific goal helps make the slip-box system deliberate practice. However, none of these skills can be measured objectively—and so the slip-box system does not constitute deliberate practice. In fact, Ericsson himself wrote that knowledge work cannot constitute deliberate practice for that exact reason.

3. The Slip-Box System Helps You Make Good Choices

Ahrens contends that regularly using the slip-box system improves your ability to make good choices when working on your manuscripts. Ahrens explains that writers need to learn how to make good choices because writing often requires you to make judgment calls: For example, if you come up with an idea, you must decide whether it’s worth pursuing further research on or likely to be a dead end.

(Shortform note: Ahrens focuses primarily on how using the slip-box system improves your ability to choose what ideas to pursue, but how do you make better choices about which words can best express those ideas? On Writing Well author William Zinsser recommends emulating the writing style of your favorite writers: As you copy them, you’ll naturally develop a sense of what works and ultimately make better choices in your own writing.)

Ahrens contends that the best writers improve this skill by following their intuition, which they develop by repeatedly making and learning from their mistakes: The more mistakes you make, the better you become at detecting what not to do when some pattern arises—so the better you become at recognizing—or intuiting—what to do instead. Since using the slip-box system gives you constant feedback, you are constantly recognizing and learning from your mistakes: For example, if you regularly run into dead ends when researching ideas that arise in your slip-box, you’ll eventually start to intuit when an idea is likely to result in a dead end. In this way, using the slip-box system hones the intuition you need to make good choices.

(Shortform note: Relying on your intuition can harm your output, as psychologist Daniel Kahneman warns in Thinking, Fast and Slow. Like Ahrens, Kahneman contends that humans develop intuition as long as they are in predictable, regular environments that provide fast feedback and practice long enough to learn these irregularities. However, he warns that if you influence the outcome, you may learn the wrong lesson. In the example above, you may wrongly intuit that an idea will result in a dead end when, in actuality, the real issue is that you’re using ineffective research methods.)

#5: The Slip-Box System Mimics Your Brain

Ahrens contends that the slip-box system fosters creative insights by mimicking how your brain works. Ahrens explains that learning in the brain involves connecting new information to information you already know.

(Shortform note: This is why memorization techniques ask you to connect new information to information you already know: The more connections a bit of information has in your brain, the more likely you are to remember it.)

In contrast, creativity involves connecting various pieces of information in original ways. Ahrens adds that most creative insights result from thinking a lot about a particular topic, then connecting those ideas to something new in an original way.

(Shortform note: This is why, in Learning How to Learn, Barbara Oakley and Terrence Sejnowski recommend that experts regularly study new topics: If you are constantly focused on the same field, you’ll get stuck in a rut—but if you study a new topic, you’ll naturally relate new concepts to what you already know and gain new, creative insights.)

How does using the slip-box system mimic this structure? As Ahrens notes, the process of filing your notes in the slip-box encourages both learning and creativity: You must think deeply about how your note connects to other notes in standard ways, which fosters learning, and unique ways, which fosters creativity.

Additionally, actively looking through the notes in your slip-box and trying to relate them to each other increases the likelihood that you’ll relate them in a unique, creative way. This is especially true because the slip-box, as an external depository of your thoughts, contains ideas you’ve created but might have forgotten about: Seeing the notes reminds you of older ideas—and the more ideas you can remember, the more likely you can connect them uniquely to each other.

How the Slip-box System Might Help You Manage Your Attention

Ahrens’s description of how the slip-box system mimics your brain suggests that this system fosters the two ways of managing your attention that productivity expert Chris Bailey describes in Hyperfocus: hyperfocus and scatterfocus.

When you hyperfocus, you deliberately direct your attention to a single task. Filing the notes in your slip-box—at least when you’re thinking deeply about how your note connects logically to other notes in your slip-box—may encourage hyperfocus.

In contrast, when you scatterfocus—or intentionally mind-wander—you don’t focus on a single task and instead leave some brainpower available for your attention to roam. You can intentionally mind-wander with the goal of increasing creativity—and the slip-box system appears to foster this intentional mind-wandering.

For example, Bailey recommends using the Zeigarnik effect we discussed previously to your advantage: He explains that if, thanks to the Zeigarnik effect, your brain is subconsciously working on a problem, you’ll automatically connect all the stimuli you encounter to that problem in an attempt to solve it. As such, he recommends intentionally mind-wandering in busy environments to maximize the stimuli you encounter—and thus maximize the chances you’ll have a creative insight. Similarly, your brain may treat reading the notes in your slip-box as an unfinished task, and looking through the notes may act as a “busy environment” given that each note is a stimulus that could trigger a creative insight.