Systematic literature searching for health and life sciences students

Reviewing and evaluating your search results

Once you have carried out a search, you will need to review and evaluate the search results, to see if they look relevant.

It could be helpful to:

• check how many results you have and decide if there will be enough or if you have too many.
• look at the first page of results and see if they seem relevant to your topic.

If you have too many or too few results and/or they do not seem relevant, you may need to go back to your plan and rethink the search strategy/keywords you have used in your search. You could also use some of the pre-defined limits available in the databases (if available). 

A critical thinking checklist can help with evaluation of the research. Critical appraisal, and suitable frameworks, can also be used for more in-depth analysis of the research methods used.

Viewing your search results

To help you decide how useful the results are to your research, you should start by reading the titles and the abstracts (usually available in the databases). Sometimes an abstract may not be available, or you may need further detail, so you will need to open and read the full text. The written guidance below explains how to view the full text of resources found in the online databases. 

Managing Duplicates

If you are searching across more than one of the EBSCOhost databases (e.g. CINAHL and Medline) at the same time, there might be some duplicate records in the results. You can see how many duplicates there are, using the EBSCOhost platform. This short video explains how to work out how many duplicates there are in your results, as well as see how many results come back from each database searched.

If you are searching databases across more than one platform (e.g. CINAHL (EBSCOhost), Embase (Ovid) and Scopus (Elsevier)), you will need to manage your duplicates in a different way. See the Managing the search results page for more information on some ways to do this.

Reviewing your search results

Once you have completed your search, you may need to refine/edit your search in order to get the best results.

If you have too many results:

• Check that you have used the correct Boolean operators. Using OR brings back more results whereas using AND brings back fewer results.
• Consider using phrase searching. A phrase search for “skin cancer” will bring back fewer results than searching for skin AND cancer. Phrase searching only brings back results where the keywords appear side by side in the order you have written them (remember, the symbols used for phrase searching may be different in each database).
• Think whether your keywords could be more specific. For example, jogging is a more specific term than a broader keyword such as exercise, but it may be more relevant to your research and could help to focus the results. 
• Decide if adding another concept onto your search, such as a setting (e.g. hospital) or an age range, would be useful.
• Look at the pre-defined limits in the database (such as date range) and see if they could help make your search more specific.

If you don’t get enough results:

• Check your spellings are correct as the databases do not autocorrect.
• Check that you have used the correct Boolean operators. Using OR brings back more results whereas using AND brings back fewer results.
• Make sure you have used synonyms/alternative keywords for your research terms.
• Consider using truncation as this will broaden out your results. For example, a search for anxi* will find research which contains the keywords anxious, anxiety and anxiousness (remember, the symbols used for truncation may be different in each database).
• Think about using wider terms to describe your keywords. If you have used a specific term such as jogging, you could broaden it out by using a wider term such as aerobic exercise or exercise (as long as that is still relevant to your topic).
• If you are using a framework, such as PICO, you don’t have to put all of the terms in your search for each element. Look at your results to decide.
  • This could happen if you have a very specific population group, intervention or outcome. Or, when you are comparing two interventions.
  • For comparison questions, if there are not enough papers which compare the two interventions, you may have to do the comparison yourself. You can try two searches, one looking for research on the intervention and one looking for research on the comparison, or you could combine the comparison and intervention terms with OR to bring either term back.
• Consider removing any limits (such as date range) or additional concepts (such as a setting).
• Try searching across more than one database.

• the full text limit, will restrict results to the full-text within that specific database, whereas there could be access via another database (or through inter library loan).
• the geography limit will restrict results to the area where the journal was published, not to the area where the study took place. Therefore, if you want to limit the results to a particular region, it would be better to treat the location as an additional concept and add it onto your search strategy as you have done with the other concepts. 

Checking your search strategy

If your search results are not what you were hoping for, you can also use the search strategy checklist to review/amend your search.

Critical thinking

To help you think critically about what you read and ask the right questions, you could use a checklist when reading research. The checklist helps you evaluate your sources of information in terms of quality and relevance.

Using the checklist, you are guided to look for meaningful information in the research by breaking down the 4 elements into specific questions regarding:

• What? What type of source is it (is it peer reviewed)? What approach has been taken to produce the results
• Who? Who wrote or produced the source? Who is the target audience? Does the author have an agenda/bias?
• When? When was it published or last updated? Is the information still accurate?
• How? How was it written? Is it based on evidence rather than emotions? How was the data gathered and analysed - are they recognised research methods for the subject area?

The full checklist can be accessed below.

Critical appraisal

Critical appraisal uses a structured approach to examine how the research has been conducted. You can use a framework to evaluate and critique the research methods used, looking at areas such as the methodology, to assess the strengths and weaknesses of the study and potential biases. 

The Critical appraisal guide provides basic level support for appraising qualitative and quantitative research papers. The guide includes frameworks to appraise research.

CASP (the Critical Appraisal Skills Programme) also provide a range of checklists which can be used for critical appraisal. The link to access these checklists can be found below.