How much literature is “enough”?

One way to approach this question is to say that there is no clear answer as to how much literature is enough. But we can, just as a thought experiment, try a few different answers and see what insights come out.

Let’s start with a reasonable guess… Let’s say you need 200 references in total throughout your thesis. The next question is which 200? In many fields, there are thousands upon thousands of possibly relevant sources. So even if you include 200, you’ll still have to exclude most of them.

Now let’s go to an extreme and say you need 2000 references. This lets you cover a lot of ground, but it will be impossible to cover anything in depth. If you were to give a summary of each individual source, you’d drown in detail and there would be no space left for your own original work, so what you would have to do is write about the literature as a whole. Taken collectively, what does the research say? What are the trends in the literature and what are the kinds of questions being asked?

Finally, let’s go to the other extreme and say you can only include 20 and no more. What can you absolutely not leave out? Which sources are crucial to your work? Which are the best, most relevant, most useful? These you could go into in much greater detail.

Although these numbers are clearly arbitrary, they do tell us something useful about the skills you need for a good literature review.

  • You need to leave out most of the literature and focus on the best and most interesting work
  • You need to be able to summarise wide areas of the literature by focusing on the trends, rather than individual papers
  • You need to know which sources are the most important and say more about these
See also
How much literature is enough? My 2015 answer
How to write a compelling literature review
How to read a journal article
How to write a PhD literature review (a 2-part course)

How to do world-changing research

Most research is incremental, but that doesn’t mean it’s not important; the gradual accumulation of knowledge through collective effort is how society progresses.

But every now and then, someone does something that blows the field apart; fundamentally changing the way the field thinks about and carries out research.

Often, this comes about from questioning, testing or abandoning a long-held assumption.

This is not an easy path. In order to publish your work, you have to get it past your peers. Any paradigm-changing ideas will always, rightly, be held to a higher level of scrutiny, but it’s also worth noting that these are, potentially, people who have built their career and reputation on the status quo.

In principle, reviewers should be impartial, focusing on the ideas and the quality of the research above all else. But this just isn’t the way humans work. In general, we’re very good at rationalising emotional reactions. An academic with a position to protect is even better at it (even if they don’t realise what they’re doing).

But there are always a few. A few who are open and secure enough to be interested, then convinced. It’s those first, brave few who will spread your idea.

So it’s not enough to do the work. It’s not enough to be brilliantly insightful and meticulous in your analysis. You have to sell your idea before it can change the world. You have to fight through the rejection and find the few who’ll listen.


We are losing the ability to daydream.

Next time you’re waiting (for a train to go, or a bus to come, or a plane to go), take a look around. How many people are staring at a screen?

It’s a habitual response. When we don’t know what to do, we reach for the phone.

But what if you don’t? What if you leave it turned off, and let yourself daydream?

It’s when the pressure’s off, when you have time and space to play with ideas, that inspiration can strike.

Your attention is the most valuable resource you have. Don’t give it away so cheaply.

See also:
Beyond the obvious
Time to think

The value of a PhD

What’s the value of a PhD?

For some, the value is clear. You want to do pharmaceutical research? Get a PhD and it’ll open up the possibility of a well-paid career.

For others, the value of a PhD comes from the way it’s perceived by others. It’s perhaps less quantifiable, but in some circles the status of having a PhD can be more valuable than the skills you developed on the way.

Then there are some for whom doing a PhD carries no obvious economic, social or practical benefit. It’s expensive, time-consuming and stressful, so why do it if there’s no tangible gain?

The value of a PhD, here, is whatever you believe it is. It comes from the story you tell yourself about what it means to be the kind of person who has a PhD. This is as good a reason as any to do it (and certainly more interesting than a cost-benefit analysis).

Other people with different beliefs and different stories might never understand, but that’s OK.

See also:
The “good” PhD student

The minimum viable chapter

When writing, it’s common to worry about whether you have enough.

What if I miss something the examiner wants to see?

This way of thinking leads you down a difficult path, always working to add more rather than presenting what you have.

Instead, think about the minimum you need. What are the most important things you have to communicate? What are your best, most interesting results? Focus on these, and don’t dilute the good stuff through fear of it not being enough.

See also:
What to do when your PhD project gets too big

How to build your bibliography from just one paper

Most journal articles aren’t that important. Reading them (or not reading them) has no real impact on your research.

But, occasionally, you will find a paper that just fits. It’s relevant. It’s high quality. And most importantly, it influences the way you think about or go about your own research.

There will be relatively few of these (perhaps 5 or 10 in total during your whole PhD) but the impact they have is massive.

Once you’ve found one of these papers, (let’s call it paper A) you can use it as a seed to grow the rest of your bibliography. Here’s how…

First, look at the references in paper A. If the work is highly relevant to your own, the chances are they will cite other sources that are relevant to you. They have already read through the relevant literature and are telling you where to look.

Then, look up the authors of paper A; what else have they published? What do their departmental or LinkedIn profiles say they are working on now? This is not only to find other potentially relevant articles, but also to get to know who is working on similar topics (the field consists of people, and you need to know who they are).

Finally, look at who else has cited paper A. Most academic search engines and many journal pages include “cited by” information for each source. Anyone else doing similar work to you is likely to cite many of the same sources, so this is a good way to find results that you may not have found through a search engine.

This final step can also give you an indication of how paper A has influenced the field. It’s also a good step to repeat to find out if anything relevant has been published recently (after you submit your thesis but before your defence, for example)

If you repeat this process using the best papers you find, you can quickly find a good number of other high-quality, highly relevant sources. This doesn’t replace keyword searches, but it’s a very quick and very effective addition.

See also
Searching for literature: Why google scholar is a blunt instrument
How to read a journal article
Filtering the academic literature


Live Q&A sessions

I’m thinking of doing live Q&A sessions. You can submit questions in advance, then everyone gets to hear the answers and join in the conversation.

Before setting this up, I’d like to gauge interest. Enter your email below and I’ll let you know when the sessions are going ahead. Your email will only be used for updates about free live events, nothing else!

How to compete in academia

It’s not by doing more of what everyone else is doing. It’s not about doing more unpaid administrative overtime than anyone else.

It’s by doing important work that people beyond your department will care about.

This means that you have to protect your time and attention. It means sometimes saying no (or not now) to other people, or just turning off email for a while so you can do your thing.

See also
From PhD to postdoc
3 harsh truths about academic careers (and how to succeed)

How to write well: solving problems of expression

Writing is about solving problems of expression.

The difficulty of the problem depends upon the difficulty of the idea you want to express. Some thoughts are easy to put into words; the ideas you know well, have confidence in and have explained before. Other ideas take much more work, maybe because the thought isn’t fully clear to you, or because it is a subtle point or requires deep insight. These take much more thought, effort and time.

If you only write fast, then you will only be able to write about the things that come easily to mind, and you will never be able to reach those deeper insights, nor be able to express those difficult concepts adequately. It you only write fast, then you are denying yourself the opportunity to solve those more difficult (and often important) problems of expression.

A lot of writers get frustrated if they can’t maintain the same pace, but in order to write well – and to cover the full range of difficulty – you must allow your pace to vary with the difficulty of the ideas you are trying to express at any given time.


See also:
How to find your writing flow
How to overcome writer’s block