Searching for literature: why Google Scholar is a blunt instrument

If you’re going to use a tool to help you with an important part of your research, it helps if you know a bit about how it works.

Searching for literature is a major, time consuming, and vital part of any PhD, so your choice of search tool matters.

There are some major drawbacks to using Google Scholar. That doesn’t mean you shouldn’t use it, but you should know what it’s weaknesses are.

The Google Search Algorithm

When you do any kind of search through google, their search algorithm decides in what order to show you the results.

It’s an incredibly sophisticated system, taking into account all kinds of measures of importance and relevance for each search result. But here’s the problem…

Nobody knows what the algorithm is. So you don’t know how they’ve sorted them, and you have no control beyond selecting the search terms and what years to search.

An example

If I search for “scanning tunneling microscopy”, then I recognise some of the top results (including the nobel-prize-winning inventors of the technique). There are papers there which have been cited hundreds or even thousands of times. So far so good.

But there are articles there that (with all due respect to the authors) have no business being in the top 10.

Why Google ranks a paper with 3300 citations at number at number 6, and a paper with 21 citations (from 1990, so it’s had plenty of time to have more of an impact) at number 7, is anyone’s guess.

This stuff matters. There are over 200,000 search results, so if google is filtering and sorting the results for me, I’d first I’d like to know how, and second I’d like to be able to play with the settings to sort results the way I want.

The advantages of Google Scholar

Well it’s free, so anyone anywhere can use it (even if you have to pay for access to some of the results).

And of course you can change the search terms you enter to get more specific results (but that’s not really an advantage as you can do that with any search engine).

Alternative Tools

I always used Web of Knowledge, which gives far greater control and transparency over search results. It requires a subscription, but if your institution is registered then definitely use it.

The key thing is being able to control how search results are presented to you. Leaving it up to Google is not PhD-level thinking.

I’m going to throw this one over to you in the comments section. What tools do you use to search? And why?

 

Leaving your thesis introduction till last? It could be a mistake…

The introduction to your thesis is the first thing the examiner will read. It’s your only chance to form a first impression, if the examiner doesn’t already know you. It sets the background, context and motivation for your work. And so it’s at least as important as every other chapter.

And yet a lot of people leave writing the introduction till last and if you’re near the deadline, it’ll be written in a rush. This is a mistake. If you write your introduction as a hurried afterthought, or as just a dry list of things that will be covered later then they will want to skim read it to get to the proper work in later chapters.

It is far better to write an engaging introduction, having spent time thinking about why your research matters and why anyone would want to read about it.

Why you might write the intro last

If you are writing chapters but you don’t yet know the full story, then it might make sense to write the introduction last.

If you’re doing this, I guarantee you will be stressed in the run up to submission. Why? because you’re trying to finish the research and the writing all at the same time.

It’s like cooking for a dinner party and constantly running out to buy ingredients while the guests are arriving. It’s not going to end well!

Stop, finish your research, then resume writing once you know what you’re going to say.

Writing an engaging thesis introduction

The job of the introduction is to make the reader want to read the rest of the thesis.

Examiners are busy people. When your thesis arrives on their desk, there will be that moment of dread… will this be an interesting read, or will it be like wading through wet cement?

A good thesis introduction will set up a sense of anticipation.

Why is this work important? And why should anyone care?

Here are a few tips to help you write an engaging introductory chapter:

1. Start with the big picture

Start with an idea of how the whole thesis will be structured. What will be covered in each subsequent chapter? Then when you talk about specific concepts in the intro, you can say “this will be discussed further in chapter …”.

Without these references to what you will cover later, the examiner might be wondering, “why are you telling me this?”

2. General > specific > general

A good structure to follow for the chapter is to start broad. Why does your field of research matter to the wider world?

Then you can talk about specific things related to your niche, and say why those matter to your field of research.

Then at the end of the chapter, try to link your specific niche back to the general, wider world again.

3. Give them something unexpected

Examiners have read a lot about your subject, but they don’t know you.

Give them something unexpected; a unique perspective, something that interests you or that you find fascinating, and they will be interested to read more.

4. Set boundaries

At some point early in the chapter (but not necessarily the first paragraph) tell the reader what you will cover in the chapter.

In my thesis, I included the following paragraph after a brief introduction of about 2 pages as to why nanoscience and nanotechnology matter:

Though there are several excellent general reviews of nanoscience and technology
(3–6), each to some extent reflects the authors’ personal research interests
and expertise. Due to the pace of development and breadth of research,
a truly comprehensive review is probably impossible, and certainly beyond
the scope of this thesis. The following brief review presents the properties
of semiconductor and metal nanostructures, in addition to the principles of
self-assembly and self organisation.

So I set out clearly what the review would cover, while pointing the reader to more general reviews for reference.

This meant I could be highly focused on specific principles, but also relate these back to the general motivation of the field.

It helps if you know what you want to cover, and how it relates to your research!

5. Relate your work to the best in the field

When you talk about the state of the art in your field, focus on the very best work.

This not only reduces the number of papers you have to reference, but it gives your thesis a feeling of quality by association. It shows that you have some standards and appreciation for good research.

Say why that work matters, and you help to justify your own.

6. Where are the gaps?

Once you’ve talked about the best work in the field, what gaps in the knowledge remain?

This is where you introduce your work:

Although giant strides have been made in recent years in the field of …, there remains an open question as to …

The work described in the following chapters attempts to …

7. Tying it up and introducing the next chapter

Your introductory chapter needs a conclusion, but it also needs to set up a sense of anticipation. You want the examiner to want to read the rest of your thesis (or at least the next chapter).

So it’s good to summarise the general principles you have just introduced, state a problem or question that needs an answer (and why it matters in relation to the general aims of your research field), and give a quick hint of how the next chapter will help to answer that question.

If man-made nanostructures are to follow a similar path [to nature], exploiting guided self-assembly to rapidly form functional structures, we must study both the physics of structure formation at the nanoscale and the influence of structure on function, specifically optical and electronic properties.

Scanning probe techniques provide a versatile means of characterisation of these structures.

Specifically, scanning near-field optical microscopy (SNOM)
provides a means of optical characterisation with resolutions beyond the classical diffraction limit, in parallel with topographic information. These techniques, along with synchrotron based spectroscopy to probe deeper into the
electronic properties of nanostructured assemblies, will be discussed in the following chapters.

Does this structure work?

My examiner wrote in his report that the first chapter of my thesis was one of the best introductions to the subject he had ever read, including those published in the literature.

I was never a particularly good physicist, compared to some of the people I have worked with. But first impressions count, and introductions matter.