My question is : What is a time effective way to learn new material/ reviewing old material you don't completely remember?


For my research in Computer Science, I need lots of elements of hypothesis testing that I learnt in Statistics 101 (Roughly 10 years ago). I haven't taken a single stats class ever since. I vaguely remember the terms involved in the subject and am somewhat conversant with the basics of statistics (so I don't need to retake the course). But all in all, it's as good as a blank slate right now.

I have read How to efficiently read mathematically and theoretically dense books in STEM fields? but that targets a specific topic that the OP wants to learn, not an entire book. The top 3 answers talk about reading only those sections which you are interesting in. I, on the other hand, need to understand the whole of hypothesis testing which by itself is a book.

My options are (As far as I can see):

  1. Take out the book I used / "Best" book of the subject (i.e. the one best suited for my background) and read it from page 1 till I am comfortable. Too time consuming

  2. Read the chapter I need and then go back to the terms I don't understand. Time spent in confusion and direction-less reading exceeds the time actually spent adding value.

  3. Take course again/Read cover to cover. God No.

  4. Any other?

EDIT : I wish to add that I can sacrifice depth for familiarity and savings in time. (Is this a good idea but? Assuming that it's not a central part of my research)

  • 2
    Note that (1) and (3) follow a likely incorrect assumption that what the book/course deems important is what you need to know. Once a course is over, most books/courses are best used as reference material for you to look up material on a need-to-know basis.
    – eykanal
    Commented Jul 9, 2012 at 12:26
  • 2
    I disagree with the characterization "Time spent in confusion and direction-less reading exceeds the time actually spent adding value". First, the process you're describing isn't directionless at all; you're explicitly moving in the direction of greatest ignorance! Second, confusion is valuable. It's uncomfortable as hell, sure, but that's precisely what makes it valuable. When you finally come out of the fog, you own the ideas you were confused about. Failure is the best teacher.
    – JeffE
    Commented Jul 9, 2012 at 16:24
  • Also, why do you prefer learning fast over learning well?
    – JeffE
    Commented Jul 9, 2012 at 16:27
  • @JeffE. I would love to study it well but I'm not sure I'd want to spend a month reading something that is only tangentially useful.
    – user107
    Commented Jul 9, 2012 at 16:40
  • 1
    @Inquest: And how do you know that something you don't understand is only tangentially useful?
    – JeffE
    Commented Jul 9, 2012 at 17:08

4 Answers 4


First of all, you will spend virtually your entire career doing this (trying to remember stuff you forgot), so this is a question that's worth really working on. You'll hopefully receive a good few answers; try them all over the course of a year or two in different situations and choose the one that works.

My personal method is very similar to your (2); review the specific parts of the material that you need to know for that specific situation. In most cases, you'll find this to be sufficient for solving a particular problem. If you don't understand your material, then either Google the topic and try to read someone else's overview, or simply take a step back and go over the more fundamental material, working your way back up to the topic at hand.

Note that this will not work for situations where you need everything, such as interviews. For those, you'll want to read outlines and try to summarize contents for yourself. I've also gone back and looked at homework problems, which (assuming they were well-written assignments) can provide you with a good overview of the material that you need to know about the topic.

  • after textbooks and google, one or more SE sites can help fill in the gaps for a specific question. I find this often very helpful for more specific academic applications. Commented Jul 9, 2012 at 18:24

Let me answer a different (but related) question. How can you learn material now so that you'll be better able to recall it years from now? Here I recommend that you explore to discover your own learning style, which has a couple key advantages.

  1. Using the right style can help you to absorb information more quickly and retain it longer.

  2. Perhaps more importantly, by recreating the techniques you used to learn the material, you can more easily recall it.

A simple example of (2) is that if you learn certain material while listening to classical music, then later you'll be better able to recall it while listening to similar music. This may sound obvious, but far too few people make use of it. Let me give a personal example. Like many people, I retain information far better if I interact with it: take notes, draw diagrams etc. This process can be time intensive, so you have to find a balance. What was terrible though, was that I would often lose my notes, so that when trying to recall the information later I'd be stuck.

Only after I was well into grad school did I settle on marking extensively in my books. I underline, draw arrows, mark key ideas with boxes and stars, etc. The magic is that when I reread later, my markup helps me to quickly remember what I was thinking when I first processed the concepts. So whatever epiphanies I had the first time around are more readily accessible. My point isn't to tell you to mark in books (though I find it invaluable). My point is to tell you to recall information in a way similar to how you learn information.

  • This is a very useful point - a preventative approach Commented Jul 9, 2012 at 18:26

You didn't really mention WHY you need the material for your research.

One case is when you have this vague feeling that there's a concept from statistics (in your case, hypothesis testing) that you need for your work. In that case, eykanal's approach and strategy (2) is best. Focus on what you need, and do deep search, taking detours when needed to understand ancillary concepts.

Another case is when you're moving into a new area and expect that you'll need a firmer base in the material before you can continue (to develop the right intuitions and so on). In that case, strategy (2) is still ok, but it helps to do some background work on the side. I find that working through problems is a good way of keeping you focused on learning by doing, and also tests your fundamentals.

  • I need it because I feel my thesis is drifting in that direction but as of now, it's fairly basic stuff.
    – user107
    Commented Jul 9, 2012 at 16:44

Tablets make it a lot easier to go through old materials. If you can find ways to download your textbooks and lecture notes as PDFs and then use a tablet to heavily annotate your textbook (you can even insert extra pages too), you can come up with an easily-searchable annotated version of your textbook that you can re-use again for years to come.

I use a Lenovo ThinkPad because of its large screen size and stylus pen, which makes it very easy to annotate and highlight textbooks and lecture notes. I also put my textbooks in my Dropbox folder so that my annotations are auto-saved in my Dropbox (and in case I ever lose my tablet, I won't lose my textbooks along with them).

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