Can I conduct a Systematic Review as my Master’s dissertation or PhD thesis? Yes, It Depends!

First, when talking about the systematic review, I refer to it as a process, not a product. You may follow the systematic reviewing process, but the product may be called a scoping review, an umbrella review, a network meta-analysis, a realist review, an evidence gap and map, a systematic review and so on. So it does NOT mean that just because you follow a systematic process in your literature review, you should call it a systematic review! Find the best name for your academic child.

Second, although I wrote this post on systematic review and evidence synthesis; however, its content could be generalised to any secondary study which is based on already existing data, including scientometrics, bibliometrics, altmetrics, content analysis, data mining, process mining, etc.

I structure this post based on Rudyard Kiping’s six serving men: What and Why and When And How and Where and Who! If you don’t have time to read this, I respect that; please don’t waste your time and jump to Conclusion :D

What: An entire dissertation or just a chapter?

Yes, both are possible.

My bachelor’s dissertation was a report on ‘censorship’, and its entirety was a literature review. I got a full mark on it in 2008. I published it in 3 pieces in a print-only students’ magazine (Papyrus). Currently, I see medical and undergraduate students who conduct systematic reviews as their projects. Some are serious and end up publishing their work.

My Master’s dissertation on ‘clinical librarianship’ had 5 chapters, and the 2nd chapter was a literature review. I presented the findings in several conferences, but busy with getting a job, I never found time to publish it. I knew some of the students who had their Master’s thesis as a full systematic review. Indeed, I supervised several Master’s students and a few MD (medical doctor) and clinical residents between 2010 and 2020.

In 2020, My PhD thesis on ‘study-based registers’ was more about systematic review methods, but I extracted data/meta-data from about 20,000 studies and cleaned, curated, and analysed them. I stored the data in a database that looked like an evidence gap and map — a type of evidence synthesis — or an extensive scoping review. It took 7 years between 2013 and 2020, and all parts of my PhD dissertation are now published as 9 papers. The majority are methods or discussions, and a few are in traditional research study format with data and analysis.

Between 2011 and 2021, I supervised some PhD students who had a systematic review as the second chapter of their dissertation. It has become a routine and acceptable practice.

On the other hand, I am aware of PhD students who successfully finished their PhD conducting or contributing to several Cochrane reviews or leading a large network meta-analysis that took 3 years to finish with 2 update searches.

Yes, it is possible to have a systematic review as your PhD dissertation; however, be careful what you wish for. You can become a professional in systematic reviewing or learn other quantitative and qualitative study designs during your PhD studies alongside systematic reviewing. Find the best fit considering your interests and future career. Get the best value for 3–7 years of your life spent on PhD.

Why: Why a systematic review? Is it the best option?

Usually, your research question or topic should be based on your interests, a real-world need, or a real-world problem.

Most research studies start with a question and then we ask what is the best study design and research method to answer that question. Not the other way around!

Of course, all research requires a proper systematic literature search, and that’s why we call them ‘re-search’! You can do ‘research’ only if you have done the ‘search’ first and have found no answer. Such search would stop you from re-inventing the wheel or, worse, re-inventing the flat tire — as Dr Andrew Booth puts it.

If your question is to find out the number of homeless people who sleep on the street in your town/city centre on a nightly basis across the year and assess their needs, a systematic review may not help.

Many criticise systematic review as an ‘easy choice’ for lazy students to go for it rather than bother with “real” research! Their excuse is that you will be awarded the same masters or PhD degree at the end of the day! A systematic review is a real research [a discussion for another time], which may be more complex than primary research and may take much more effort than primary research.

Story: When I was a master’s, my classmates started taking scientometrics projects or projects that they could work on from home or dorm without facing people or travelling! Even supervisors pushed them towards that approach. Some of them and their supervisors laughed at why I was trying to start the first clinical librarianship project in the country, taking day and night shifts in an emergency department, even on new year’s eve. It turned out very well for me, and I defended my proposal and thesis earlier than my 11 classmates and immediately got a full-time job in 2010. Who’s laughing now — now I call scientometricians, citation counters! :D So, my primary study finished sooner than their secondary studies and left an impact that continues right today.

With pandemic, many decided to shift their projects from field work into a type of literature review. They forgot the nature of research and the fact that you can still collect data through surveys, questionnaire, and interviews online, or use an existing dataset. Don’t let the pandemic or your laziness or short-sightedness stop you from doing non-review research. Start with research question and then choose if a systematic review is the best way to answer that question. Of course you can have a systematic literature search as part of any primary research. So, a systematic review is a bonus you can get with any other primary research.

The best research method to answer a research question is not always the best theoretical research method on the paper but also the most practical one. Let’s say running a large randomised controlled trial (RCT) is the best study design to answer a question. As a master’s or PhD student or a clinician, you must either win the lottery, be wealthy, have wealthy parents, or win a big grant — yeah, you wish — to afford such study design. Practically, a systematic review of smaller existing RCTs would make more sense.

When: Do you have what it takes?

Systematic reviewing requires time, skills, resources, and teamwork. Some systematic reviews may take much longer than running a primary study. You need to be very careful about formulating your research question for a systematic review to get enough literature and fit it into your timeline. You do want to graduate, right? What if you don’t find any study to answer your questions? What if you find too many studies?

The size of your review could completely change the time you spend on the review. If you have 3 months for your master’s dissertation or 6 months for your systematic review chapter of your PhD thesis, you must consider a balance between your time and the size of your review. Unlike primary research where you calculate a sample size, the number of included studies cannot be predicted accurately in systematic reviews.

Another point to consider is that most stages of systematic reviews require 2–3 people. You need to make sure you have a classmate or another master’s or PhD student to collaborate on your review, and you can pay back by collaborating on their review. Alternatively, you can ask your supervisor to check all or part of your work.

As another pre-requisite, you need access to the databases and library services, for example, to get training on how to write search syntax/strategy, run systematic searches in these databases, and order papers that you cannot access through conventional and unconventional ways!

When you know how to conduct a systematic review, have enough time, human resources, and access to library resources, it is probably the right time.

How: There are many guidelines to conduct a systematic review.

If you are in the field of nursing or midwifery, or allied health sciences, you may be asked to follow Arksey and O’Malley framework or JBI Manual for Evidence Synthesis.

If you are working on interventional systematic reviews or a Cochrane review, you may be asked to follow the Cochrane Handbook of Systematic Reviews of Interventions.

Some may ask you to follow CRD’s guidance for undertaking reviews in health care.

For the pre-clinical and animal reviews, you may need to check SYRCLE.

If you are interested in health technologies, you may follow NICE, INAHTA, HTAi, or EUnetHTA methods.

The methods you follow for your review would also be dependent on your country, department, field of study and so on. You may find some of them more complicated, resource-intensive, and time-consuming than you expected. The choice of methods would also depend on who’s supervising you! Becasue your supervisors would usually stick to what they are familar with rather than wasting the time they already lack on learning new methods.

Where: your country, the university/institute and your department

A systematic review as coursework/project/dissertation is usually accepted for undergraduate/bachelor’s students or systematic review as the second chapter of a PhD dissertation. However, some countries do not accept literature review as a master’s or full PhD dissertations; they don’t consider a systematic review as ‘research’. It is important to check this with all involved in authorising your pass.

It usually involves devil in details when it comes to systematic review as an entire PhD dissertation. For example, in some countries, the regulation is about the time spent on the work (3–5 years) rather than study design or research methods.

Other’s have limitations in specific fields, so in humanities and social sciences, a massive literature review with well-constructed critical appraisal, essays and debates could be acceptable in some universities as a PhD dissertation.

If your institutional and departmental regulations allow, it is possible to have a systematic review as your undergraduate or postgraduate dissertation. Unless it is against their strategic plan! For example, some departments prefer to send their students out to the Wild — read Field — to collect data from people via survey questionnaires, checklists, observations and interviews or ask them to use existing datasets to analyse them to find patterns to meaningful relationships/associations or causation between two variables.

Some divisions and departments believe that having skills in the field may serve their graduates much better in the real world than “sitting behind their laptops and reading summarising papers” — I guess this is the wording to use if you want to offend systematic reviewers or evidence-based practioners! They might be right to send their students into wilderness with no or little funding; because that is their future if they pursue a career in Acadmia :D

Usually, it is expected of a PhD candidate to conduct a proper literature review in an organised way. It makes more sense, and it is globally accepted to have a systematic review chapter as part of the PhD dissertation; however, having a systematic review as an entire dissertation requires convincing your supervisors, examiners, and institute. It is probably more possible to get a PhD in evidence synthesis.

I have seen a few rare cases that PhD candidates have conducted one or more systematic reviews as their whole dissertation. One had a network meta-analysis with over 200 included studies and published four methods papers on network meta-analysis. Another candidate conducted 3 Cochrane reviews.

Who: Not for fainthearted!

Lie #1: Systematic review is easy and suitable for busy and lazy people.

Am I making it a big deal that a systematic review requires personal characteristics that many lacks or need time to gain?

You need to allocate lots of time and be very organised at what you are doing and keep the records of numbers and details.

Dear Rebels, you must follow the rules and a protocol and document everything. If you change the process / protocol, you should document the reason.

You may need to read a paper more than once in detail and collect the details like pieces of puzzles spread all over the place.

You may need to sit behind your desk for hours. If you are the one who get bored easily, you should discipline yourself.

You will be allowed to use all the swear words against the researchers with bad writing / reporting skills as long as you don’t say or write these words :D

You should be able to critically appraise others work and be ready to be criticised for your own work.

Many find systematic review so boring and time-consuming that are happy to pay someone to suffer on their behalf. They are missing all the fun we have.

A systematic review may find many or no studies to answer the questions. You need to have plan B if you end up with an empty or an extensive systematic review.

Conclusions

With thanks to Rudyard Kipling, please collect the following information to decide if you can and should conduct a type of systematic review or evidence synthesis as your thesis dissertation:

1. Choose your research question first and then seek a research design that would fit best to answer that question, not the other way around. The best fit could be primary research such as a cross-sectional questionnaire or a secondary study such as a systematic review.
2. Your entire thesis can be a Systematic review or contain a systematic review chapter or component.
3. See if it is acceptable to have a systematic review as a dissertation/thesis across your country, university/institute, and division/department for bachelor’s, masters or PhD degrees? If so, under what circumstances?
4. Do you have what it takes? A research question, lots of time, skills, interests, motivation, patience, personal characteristics, access to databases and library services, a supervisor familiar with at least one reference method to conduct the systematic reviews, and at least one person to help you with the tasks that require 2 people?
5. Although you follow a systematic reviewing process, your final output may be called a scoping review, an umbrella review, a network meta-analysis, a realist review, an evidence gap and map, a systematic review and so on.
6. While you have a sample size for a primary study, you will not know the number of included studies in your review. So your systematic review may end up with zero or 200 included studies and may not match the 3–6 months that you have to finish your review. Would you take that risk, and do you have a Plan B?

The systematic review is not necessarily easier or more complicated than any other research method. Don’t base your decision on rumours only on reason and passion.

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