This Study Guide explains why literature reviews are needed, and how they can be conducted and reported. Related Study Guides are: Referencing and bibliographies, Avoiding plagiarism, Writing a dissertation, What is critical reading?What is critical writing?
The focus of the Study Guide is the literature review within a dissertation or a thesis, but many of the ideas are transferable to other kinds of writing, such as an extended essay, or a report.
What is a literature review?
The ability to review, and to report on relevant literature is a key academic skill. A literature review:
- situates your research focus within the context of the wider academic community in your field;
- reports your critical review of the relevant literature; and
- identifies a gap within that literature that your research will attempt to address.
To some extent, particularly with postgraduate research, the literature review can become a project in itself. It is an important showcase of your talents of: understanding, interpretation, analysis, clarity of thought, synthesis, and development of argument. The process of conducting and reporting your literature review can help you clarify your own thoughts about your study. It can also establish a framework within which to present and analyse the findings.
After reading your literature review, it should be clear to the reader that you have up-to-date awareness of the relevant work of others, and that the research question you are asking is relevant. However, don’t promise too much! Be wary of saying that your research will solve a problem, or that it will change practice. It would be safer and probably more realistic to say that your research will ‘address a gap’, rather than that it will ‘fill a gap’.
Why do I need a literature review?
When readers come to your assignment, dissertation, or thesis, they will not just assume that your research or analysis is a good idea; they will want to be persuaded that it is relevant and that it was worth doing. They will ask questions such as:
- What research question(s) are you asking?
- Why are you asking it/them?
- Has anyone else done anything similar?
- Is your research relevant to research/practice/theory in your field?
- What is already known or understood about this topic?
- How might your research add to this understanding, or challenge existing theories and beliefs?
These are questions that you will already probably be asking yourself. You will also need to be ready to answer them in a viva if you will be having one.
A critical review
It is important that your literature review is more than just a list of references with a short description of each one. The Study Guides: What is critical reading? and What is critical writing? are particularly relevant to the process of critical review. Merriam (1988:6) describes the literature review as:
‘an interpretation and synthesis of published work’.
This very short statement contains some key concepts, which are examined in the table below.
|Published work||Merriam’s statement was made in 1988, since which time there has been further extension of the concept of being ‘published’ within the academic context. The term now encompasses a wide range of web-based sources, in addition to the more traditional books and print journals.||Increased ease of access to a wider range of published material has also increased the need for careful and clear critique of sources. Just because something is ‘published’ does not mean its quality is assured. You need to demonstrate to your reader that you are examining your sources with a critical approach, and not just believing them automatically.|
|Interpretation||You need to be actively involved in interpreting the literature that you are reviewing, and in explaining that interpretation to the reader, rather than just listing what others have written.||Your interpretation of each piece of evidence is just that: an interpretation. Your interpretation may be self-evident to you, but it may not be to everyone else. You need to critique your own interpretation of material, and to present your rationale, so that your reader can follow your thinking.|
|Synthesis||The term ‘synthesis’ refers to the bringing together of material from different sources, and the creation of an integrated whole. In this case the ‘whole’ will be your structured review of relevant work, and your coherent argument for the study that you are doing.||Creating a synthesis is, in effect, like building interpretation upon interpretation. It is essential to check that you have constructed your synthesis well, and with sufficient supporting evidence.|
When to review the literature
With small-scale writing projects, the literature review is likely to be done just once; probably before the writing begins. With longer projects such as a dissertation for a Masters degree, and certainly with a PhD, the literature review process will be more extended.
There are three stages at which a review of the literature is needed:
- an early review is needed to establish the context and rationale for your study and to confirm your choice of research focus/question;
- as the study period gets longer, you need to make sure that you keep in touch with current, relevant research in your field, which is published during the period of your research;
- as you prepare your final report or thesis, you need to relate your findings to the findings of others, and to identify their implications for theory, practice, and research. This can involve further review with perhaps a slightly different focus from that of your initial review.
This applies especially to people doing PhDs on a part-time basis, where their research might extend over six or more years. You need to be able to demonstrate that you are aware of current issues and research, and to show how your research is relevant within a changing context.
Who can help?
Staff and students in your area can be good sources of ideas about where to look for relevant literature. They may already have copies of articles that you can work with.
If you attend a conference or workshop with a wider group of people, perhaps from other universities, you can take the opportunity to ask other attendees for recommendations of articles or books relevant to your area of research.
Each department or school has assigned to it a specialist Information Librarian. You can find the contact details for the Information Librarian for your own area via the Library web pages. This person can help you identify relevant sources, and create effective electronic searches:
“they help you to find information, provide training in information skills and the use of databases and can help you to develop your research skills”.
Reading anything on your research area is a good start. You can then begin your process of evaluating the quality and relevance of what you read, and this can guide you to more focussed further reading.
Taylor and Procter of The University of Toronto have some useful suggested questions to ask yourself at the beginning of your reading:
- What is the specific thesis, problem, or research question that my literature review helps to define?
- What type of literature review am I conducting? Am I looking at issues of theory? methodology? policy? quantitative research? qualitative research?
- What is the scope of my literature review? What types of publications am I using (e.g., journals, books, government documents, popular media)?
- What discipline(s) am I working in (e.g., nursing, psychology, sociology, medicine)?
You can add other questions of your own to focus the search, for example: What time period am I interested in? What geographical area? What social setting? What materials?
You may also want to make a clear decision about whether to start with a very narrow focus and work outwards, or to start wide before focussing in. You may even want to do both at once. It is a good idea to decide your strategy on this, rather than drifting into one or the other. It can give you a degree of control, in what can feel like an overwhelming and uncontrollable stage of the research process.
Ways of finding relevant material
Searching electronic databases is probably the quickest way to access a lot of material. Guidance will be available via your own department or school and via the relevant Information Librarian.
There may also be key sources of publications for your subject that are accessible electronically, such as collections of policy documents, standards, archive material, videos, and audio-recordings.
References of references
If you can find a few really useful sources, it can be a good idea to check through their reference lists to see the range of sources that they referred to. This can be particularly useful if you find a review article that evaluates other literature in the field. This will then provide you with a long reference list, and some evaluation of the references it contains.
Hand searching of journals
No electronic literature search can be 100% comprehensive, as the match between search terms and the content of articles will never be perfect. An electronic search may throw up a huge number of hits, but there are still likely to be other relevant articles that it has not detected. So, despite having access to electronic databases and to electronic searching techniques, it can be surprisingly useful to have a pile of journals actually on your desk, and to look through the contents pages, and the individual articles.
Often hand searching of journals will reveal ideas about focus, research questions, methods, techniques, or interpretations that had not occurred to you. Sometimes even a key idea can be discovered in this way. It is therefore probably worth allocating some time to sitting in the library, with issues from the last year or two of the most relevant journals for your research topic, and reviewing them for anything of relevance.
Blaxter et al. (2001:103) recommend this method, in addition to other more systematic methods, saying:
‘Take some time to browse – serendipity is a wonderful thing.’
To avoid printing out or photocopying a lot of material that you will not ultimately read, you can use the abstracts of articles to check their relevance before you obtain full copies.
EndNote and RefWorks are software packages that you can use to collect and store details of your references, and your comments on them. As you review the references, remember to be a critical reader (see Study Guide What is critical reading?).
Keeping a record
Keeping a record of your search strategy is useful, to prevent you duplicating effort by doing the same search twice, or missing out a significant and relevant sector of literature because you think you have already done that search. Increasingly, examiners at post-graduate level are looking for the detail of how you chose which evidence you decided to refer to. They will want to know how you went about looking for relevant material, and your process of selection and omission.
You need to check what is required within your own discipline. If you are required to record and present your search strategy, you may be able to include the technical details of the search strategy as an appendix to your thesis.
Plagiarism is regarded as a serious offence by all Universities, and you need to make sure that you do not, even accidentally, commit plagiarism.
Plagiarism is the using of someone else’s words or ideas, and passing them off as your own. It can happen accidentally, for example, if you are careless in your note-taking. This can mean that you get mixed up over what is an exact quote, and what you have written in your own words; or over what was an idea of your own that you jotted down, or an idea from some text.
A practical way to help you avoid accidentally forgetting to reference someone else’s work, is routinely to record short extracts of text verbatim i.e.: using the exact words of the author, rather than putting the idea into your own words at the point where you are still reading. You will need to put inverted commas (‘xxx’) around the exact quote, and record the page number on which it appears.
This has the advantage that, when you come to use that example in your writing up, you can choose:
- to use the exact quote in inverted commas, with the reference and page number; or
- to describe it in your own words, and use the standard reference format, without the page number, to acknowledge that it was someone else’s idea.
Help is available regarding how to avoid plagiarism and it is worth checking it out. Your department will have its own guidance. Further help is available from the Student Learning Centre’s Study Guide on the topic, and from our online tutorial on plagiarism.
When to stop
It is important to keep control of the reading process, and to keep your research focus in mind. Rudestam and Newton (1992:49) remind us that the aim is to ‘Build an argument, not a library’.
It is also important to see the writing stage as part of the research process, not something that happens after you have finished reading the literature. Wellington et al (2005:80) suggest ‘Writing while you collect and collecting while you write.’
Once you are part way through your reading you can have a go at writing the literature review, in anticipation of revising it later on. It is often not until you start explaining something in writing that you find where your argument is weak, and you need to collect more evidence.
A skill that helps in curtailing the reading is: knowing where to set boundaries. For example, a study of the performance of a clinical team working in gerontology might involve reading literature within medicine; nursing; other allied healthcare specialties; psychology; and sociology; as well as perhaps healthcare policy; and patients’ experiences of healthcare. Decisions need to be made about where to focus your reading, and where you can refer briefly to an area but explain why you will not be going into it in more detail.
Writing it up
The task of shaping a logical and effective report of a literature review is undeniably challenging. Some useful guidance on how to approach the writing up is given by Wellington et al (2005:87):
- “It should be framed by your research questions.
- It must relate to your study.
- It must be clear to the reader where it is going: keep signposting along the way.
- Wherever possible, use original source material rather than summaries or reviews by others.
- Be in control, not totally deferent to or ‘tossed about by’ previous literature.
- Be selective. Ask ‘why am I including this?’
- It is probably best to treat it as a research project in its own right.
- Engage in a dialogue with the literature, you are not just providing a summary.”
In most disciplines, the aim is for the reader to reach the end of the literature review with a clear appreciation of what you are doing; why you are doing it; and how it fits in with other research in your field. Often, the literature review will end with a statement of the research question(s).
Having a lot of literature to report on can feel overwhelming. It is important to keep the focus on your study, rather than on the literature (Wellington 2005). To help you do this, you will need to establish a structure to work to. A good, well-explained structure is also a huge help to the reader.
As with any piece of extended writing, structure is crucial. There may be specific guidance on structure within your department, or you may need to devise your own.
Examples of ways you might structure your literature review are:
- chronologically; although be careful not just to list items; you need to write critically, not just descriptively;
- by theme; this is useful if there are several strands within your topic that can logically be considered separately before being brought together;
- by sector e.g.: political background, practice background, methodological background, geographical background, literary background;
- by development of ideas; this could be useful if there are identifiable stages of idea development that can be looked at in turn;
- by some combination of the above, or by another structure you create.
There are many possible structures, and you need to establish one that will best fit the ‘story’ you are telling of the reason for your study. Once you have established your structure you need to outline it for your reader.
A narrative thread
Although you clearly need to write in an academic style, it can be helpful to imagine that you are telling a story. The thread running through the story is the explanation of why you decided to do the study that you are doing. The story needs to be logical, informative, persuasive, comprehensive and, ideally, interesting. It needs to reach the logical conclusion that your research is a good idea.
If there is a key article or book that is of major importance to the development of your own research ideas, it is important to give extra space to describing and critiquing that piece of literature in more depth. Similarly, if there are some studies that you will be referring to more than to others, it would be useful to give them a full report and critique at this stage.
As well as using tables to display numerical data, tables can be useful within a literature review when you are comparing other kinds of material. For example, you could use a table to display the key differences between two or more:
- possible theoretical perspectives;
- possible methods;
- sets of assumptions;
- sample profiles;
- possible explanations.
The table format can make the comparisons easier to understand than if they were listed within the text. It can also be a check for yourself that you have identified enough relevant differences. An omission will be more obvious within a table, where it would appear as a blank cell, than it would be within text.
Almost all academic writing will need a reference list. This is a comprehensive list of the full references of sources that you have referred to in your writing. The reader needs to be able to follow up any source you have referred to.
The term ‘bibliography’ can cause confusion, as some people use it interchangeably with the term ‘reference list’; but they are two different things. The term ‘bibliography’ refers to any source list that you want to place at the end of your writing, including sources you have not referenced, and sources you think readers may want to follow up. A bibliography is not usually necessary or relevant, unless you have been asked to produce one.
Help! I’ve spent ages reading up on Method ‘A’, and now I’ve decided to use Method ‘N’. I feel I’ve wasted all that time!
This experience is common in PhD study, but it can happen at any level, and can feel as if you have wasted a lot of effort. Looking at this positively, however, you have probably read more widely than you might otherwise have done. Also, it may still be possible to include some of this learning in your write-up, when you explain why you decided not to use Method ‘A’. It is also possible that, in a viva, you will be asked why you didn’t use that method, and you will be well-prepared to answer in detail.
Help! I thought I had a really good idea for my research, and now I’ve found that someone else has already asked the same research question!
That probably confirms that it was a good question to ask! Although this can feel very disappointing at first, it can often be transformed into a benefit. It is important that your research fits logically within the existing research in your area, and you may have found an ideal study to link with and to extend in some way. Remember that:
- if it (or something very like it) has been done before, and has been published, it is likely that this signifies it was a relevant and important topic to investigate;
- you can learn from how the previous researchers did it: what worked and what didn’t;
- did the previous researchers suggest any further research? If so, you may be able to link your own plans to fit with their suggestions;
- can you take the investigation further by doing your own similar research: in a different setting; with a different sample; over a different timescale; with a different intervention etc.;
- their literature review and reference list should be useful.
Help! I think I’ve got a great idea for a study, but I can’t find anything published about the topic.
Firstly, this is unlikely. Perhaps if you modify your search strategy you will find something. However, if there really isn’t anything, then you need to ask why this is the case. Check out whether there is an important reason why the research has not been done, which would make it sensible for you to choose a different focus. If you do decide to go ahead, then take extra care designing your research, in the absence of guidance from previous studies.
Blaxter et al. (2001:125) suggest that, if there appears to be no research in your field:
‘…you should probably consider changing your topic. Ploughing a little-known furrow as a novice researcher is going to be very difficult, and you may find it difficult to get much support or help.’
An important aspect of your thesis and your viva, is that you can show how your research fits with other research. This will be just as important when there is limited existing research in your area, as when there is an abundance.
Reviewing your review
Once you have a first draft of your literature review it is possible for you to assess how well you have achieved your aims. One way of doing this is to examine each paragraph in turn, and to write in the margin a very brief summary of the content, and the type of content e.g.: argument for; argument against; description; example; theory; link. These summaries then provide the outline of the story you are telling, and the way that you are telling it. Both of these are important and need to be critically reviewed.
Useful questions at this stage include:
- What is the balance between description and comment?
- Have I missed out any important dimension of the argument, or literature?
- Have I supported the development of each step in my argument effectively?
- Is the material presented in the most effective order?
- Are there places where the reader is left with unanswered questions?
- Is every element of my research question supported by the preceding material?
- Have I explained to the reader the relevance of each piece of evidence?
- Is there any material that is interesting but which does not contribute to the development of the argument?
- Have I explained adequately the justification for this research approach / topic / question?
- Are my references up to date?
- How effective is my linking of all the elements?
Beware of becoming too attached to your writing. You need to be ready to cross out whole paragraphs or even whole sections if they do not pass the above tests. If you find that what you’ve written is not in the best order, then re-shaping it is not a huge problem. It may be mainly a case of cutting and pasting material into a different order, with some additional explanation and linking. If this produces a more relevant and streamlined argument it is well worth the effort.
Blaxter L., Hughes C. & Tight M. (2001) How to research. Buckingham: Open University.
Merriam S. (1988) Case study research in education: a qualitative approach. San Francisco, CA:Jossey-Bass.
Rudestam K. & Newton R. (1992) Surviving your dissertation. London:Sage.
Taylor D. & Procter M. (2008) The literature review: a few tips of conducting it. Health Services Writing Centre:University of Toronto. http://www.utoronto.ca/writing/litrev.html
Wellington J., Bathmaker A., Hunt C., McCulloch G., & Sikes P. (2005) Succeeding with your doctorate. London:Sage
Describing Empirical Research and Critical Analysis
Illustrate a methodology: Studies that illustrate a methodology are particularly important. The limitations of a methodology can affect all studies that use the methodology. Understanding and critiquing the methodology allows the author to assess whether the theoretical claims argued by researchers using this methodology are justified and allows the reader to understand this also. Common methodological limitations in I/O psychology include: (a) use of self-report measures (limits objectivity of conclusions); use of a observational designs (limits causal inference); (b) use of university samples (limits generalisability); (c) use of a common statistical analysis technique (e.g., most people researchers using mediation or SEM do not adequately consider alternative causal interpretations); and (d) use of experiments (may lack ecological validity).
Describing an empirical study: When describing a study it is important to present only the important details. Details highly relevant in I/O psychology include: (a) sample size (will the resulting statistics have small standard errors), (b) sample type (university students, employees, etc. - will the results generalise to the target population), (c) study design (experimental, observational, longitudinal - to what extent is causal inference possible), (d) method of measurement (self-report, other report, observational, etc. - to what extent is the measure valid, reliable, measuring something real), and (e) context of research (applied, laboratory, etc. - how ecologically valid is the task) (for more info see the Social Research Methods website). Some details that are typically less relevant include the exact number of males and females in the study, racial breakdowns of the sample, and the exact scale used to measure the variable. If such details are reported, a persuasive argument is given explaining why these details may alter the results. When describing research good literature reviews provide a quick snapshot of the important elements of the research and the important findings, while at the same time not wasting precious words that could be spent on other issues. Good literature review's “don’t lose the forest for the trees”.
Critical Evaluation: Good literature reviews base claims on empirical research. Research is critically evaluated and issues such as the following are discussed: level of analysis; confounding variables; correlation or causation; mediation and moderation; generalisability; limitations of sample size; issues of measurement; implications of design (correlational, experimental); effect size and practical significance; quantitative and qualitative methods; and so on. This examination of the theoretical literature is then integrated into the conclusions reached.
Causation: Good literature reviews demonstrate an understanding of proper causal inferences. For example: It does not matter how many cross-sectional observational studies are conducted looking at the correlation between self-efficacy and performance, this does not prove that one variable causes the other. Before writing about causality consider whether X could cause Y, Y could cause X, or whether a third variables could cause both X and Y to covary. The best evidence for causal claims usually comes from experiments involving direct manipulation of the independent variable. Weaker support can come from research statistically controlling for extraneous variables and longitudinal studies. It’s also important not to trust causal claims made by many researchers, when they are conducting mediation analysis or structural equation modelling on observational data (see my discussion). Authors may argue that their data provides evidence for causal mechanisms, but at the end of the day, their research rarely allows for unambiguous causal inference. To learn about causal inference, see this post.
Causation and control: The four goals of science are sometimes said to be description, prediction, explanation and control. Understanding causation (i.e., explanation) has important implications for making recommendations for I/O psychology practice (i.e., control). For example, if self-efficacy does not causally influence performance, then attempts by organisations to manipulate self-efficacy in the aim of improving performance may be useless.
Effect Size: The research literature is filled with findings of the form, there is a relationship between x and y or there is a difference between group A and group B on some variable. Good literature reviews communicate information about effect sizes (e.g., correlations, Cohen’s d, odds ratio). This is particularly important in literature reviews concerned with the practical importance of findings. For example, in research looking at faking personality tests in selection and recruitment, reporting that (a) "student samples were able to increase their conscientiousness score on average by one standard deviation" (e.g., Cohen’s d = 1) when asked to fake is a lot clearer than reporting that "students were able to increase their conscientious score". The former reports the size of the effect, whereas the latter only reports the direction. In another example looking at the effect of different types of diversity on team performance actual correlations or Cohen’s ds from studies or meta-analyses could be reported. Effect size can also be incorporated into a style of writing which puts relationships and effects in context. Using words like "small", "medium" and "large" to describe relationships in the literature, drawing on Cohen’s recommendations for effect size, can help the reader understand the relative importance of particular relationships (see Lee Becker's notes to learn more about effect sizes).
Integration of empirical studies: Good literature reviews are grounded in the empirical literature. They highlight problems involved in drawing conclusions from empirical research . Common design limitations include: small sample sizes (inadequate power and results that are not robust); poor measures of the theoretical constructs (unreliable or invalid); unrepresentative of the domain of generalisation (e.g., a study on students applied to organisations; a study of racial diversity applied to gender diversity). Good literature reviews are critical of the ways that studies draw conclusions from empirical research.
Weaker literature reviews often treat research claims equivalently. Good literature reviews delve into the reasoning used by authors to make their claims. They critically evaluate the empirical research and develop a reasoned evaluation of the justifiability and generalisability of claims. They explore alternative interpretation of results. They identify limitations of study design.
Presenting an Overview
1) Cite meta-analyses: When the question is focused, meta-analyses provide a systematic quantitative summary of a relationship. It’s also important to know how to describe and evaluate a meta-analysis. Some major things to mention include: a) the effect size that was obtained; b) what kinds of studies were included; c) the number of studies and total number of participants; In some instances you also mention d) whether the effect size varied more than was expected from random sampling; e) results of any moderator analysis.
2) Cite review articles: Directing the reader to review articles helps provide an overview of the topic. Good literature reviews often share the conclusions reached by earlier reviews and use these as a launching pad.
3) Cite examples: Good literature reviews carefully select illustrative studies. They vary the depth of explanation given to a study. Sometimes it is sufficient to just highlight the existence of a study. For example, a literature review could include: “The relationship between x and y found in study Z has also been found in several other areas including sport (e.g., citation, citation), music (e.g, citation, citation), and physics (e.g., citation, citation)”. This style provides a review of the literature and gives the reader a sense of the breadth of work on the topic. If the reader is interested they can follow-up on one of the citations.
Synthesis: Dealing with Issues
In relation to many research questions there are findings that go for and against particular claim. For example, on the topic of the effect of diversity on team performance, there are findings suggesting positive, negative and no relationship. Good literature reviews propose plausible explanations for the variability in findings across studies based on the available evidence. Differences in findings can be explained in terms of differences in terms of study design, study conduct, and random sampling. A moderator is a factor that alters the relationship between another two variables. Moderators can be substantive (e.g., different types of participants or contexts) or methodological (e.g., different measures, software, etc.). Random sampling is also an important explanation of differences in results between studies (See my discussion of meta-analytic thinking also).
Good literature reviews weight conclusions by the quality of the evidence for alternative arguments. They recognise the value of meta-analyses in pooling multiple studies in a systematic way.
Poorer literature reviews present one theory after the next without integration. They often include text like: “despite all the research, it can not be said whether job satisfaction is caused more by situational or dispositional factors. The End…” Concluding statements, such as “more research is needed” is typical of poorer literature reviews. They also often tend to jump to conclusions too soon, often declaring a particular idea (e.g., a strong culture leads to high performance) as definitively established when debate existed. Slightly better literature reviews say things like: “This model has not been particularly supported (Smith, 2006)”. A good literature review provides evidence for why a theory has not been supported. A good literature review is aware of the relationship between empirical observations and theoretical claims.
Good literature reviews identify issues in the literature. Issues arise when two proposed ideas conflict. For example, does X cause Y or does Y cause X? Is expertise learnt or innate? Is this theory useful for practitioners or not? Is job satisfaction influenced more by dispositional or situational factors? Good literature reviews accurately and concisely summarise the major competing positions on an issue. They do not rush to conclusion, yet they do strive to reach a nuanced conclusion based on the evidence. If more research is needed, the achievements of existing research are acknowledged and concrete recommendations are made. This might be recommendation for greater use of a particular methodology or particular contexts.
Logic and Reasoning
Clear Structure: Good literature reviews have a clear structure. Aims and objectives are set out at the beginning of the literature review. The aims are consistent with the broader research needs. These needs may be derived from an assignment question, a thesis aim, or journal publishing requirements. The structure systematically works through the issues. Communicating structure both to oneself and to the reader can be facilitated by a set of headings. The structure of ideas and themes guide the literature review. Research and theory is integrated into the structure. Independent thought is reflected in the structure.
First, weaker literature reviews tend to waste words discussing material unrelated to the aims. For example, a literature review on the role of team diversity might spend many words discussing other factors besides team diversity that predict team performance. Second, weaker literature reviews are a loose listing of ideas. At its extreme the literature review appears like the author has obtained a set of articles and spent a paragraph or two discussing each with no integration. Poorer literature reviews do not demonstrate independent thought. They may mimic a particular journal article or lecture on the topic. They cite the same articles and present the same arguments as adopted in the source. At the extreme they plagiarise (i.e., copying without acknowledgement) the structure of another article.
Quality of Expression
Spelling, Grammar, Composition, Style: Good literature reviews are written well. At a basic level this involves correct spelling, grammar, and punctuation. At the next level this involves following conventions of writing literature reviews. Tense, pronoun usage, and paragraph composition are particularly important. There are many strategies for ensuring that prose reads in a structured and sequenced way (some thoughts). Finally there are many books on writing style that are worth studying from time to time (See here for a list; and here for online grammar help).
Article Deconstruction: To learn the conventions of writing in psychology, the best strategy that I know is what I call Article Deconstruction. It involves: 1) completing a writing needs analysis on yourself; 2) finding an article that demonstrates the writing style that you would like to emulate; 3) deconstructing the journal article to identify the principles that guided its creation; 4) working on your own writing task and attempting to implement the principles. A fifth step can involve reading how-to books on the particular writing task. When selecting a source article to deconstruct Annual Review of Psychology is a good place to start.
Proofreading: Authors of polished literature reviews have a system of proofreading. Simple typographic mistakes detract from the finished product. Standard strategies of proofreading include: 1) putting the literature review aside for a couple of days and returning to it to proofread; 2) reading the literature review aloud; 3) getting someone else to proofread; 4) using spell-checkers and grammar-checkers. (Here's some more proofreading tips).
References and Citations
Making the link clear: Good literature reviews clearly communicate the relationship between a statement and an accompanying citation. Is the citation a baseless assertion, an established theory, or an empirical finding? The following examples tend to be superior to ending a sentence with a mystery citation: “A study by Smith showed”, “Smith has suggested that”, “Smith has theorised”, “Smith obtained results supporting the idea that”. Good literature reviews give a sense of the strength and nature of the evidence provided by the citation. Putting an author’s name at the end of a sentence tends to not fulfil this need. Thus, the words around the citation can explain the reasons why the author asserted the idea in the first place. Did the author base the claim on common sense? Was it an empirical finding? Was it based on the summary of a set of empirical results or meta-analysis?
Poor: “Perceptual speed, psychomotor and general abilities relate to the three phases of skill acquisition in different ways (Ackerman, 1988).”
Better: “Ackerman (1988) has theorised that perceptual speed, psychomotor and general abilities relate to skill acquisition phases in different ways.”
Even Better: “Ackerman (1988) performed a series of large sample empirical studies using a range of simple psychomotor tasks which provided partial support for his theory that perceptual speed, psychomotor and general abilities relate to skill acquisition phases in different ways.”
Cited In: Good literature reviews do not use "Cited in". Literature reviews which summarise Author B’s citation of Author A’s work write: "as Author A (1999) says as cited in Author B (2002) …" . However, good literature reviews, when they see that Author B cites Author A, go and get Author A’s article, read it , and draw conclusions about it directly.
Quotes: Good literature reviews provide an independent voice on the research of others. Quotes are used sparingly and judiciously if at all. literature reviews with more than two or three quotes typically appear as if the author is unable to express an independent perspective. A simple rule is to not use quotes at all. A better rule is to use quotes sparingly and only when the particular phrasing of the original author adds value, such as in definitions or when the words have a poetic or other literary effect.
Number of References: It is important to have a sufficient number of references. The aim is generally to give an overview of the topic. The nature of the coverage and the selection procedure should be made explicit.
Independent voice: Good literature reviews carry a thread of the author’s voice. An independent voice can be facilitated by following the principles of citation mentioned above. Good literature reviews present an independent perspective on the issues. Good literature reviews answer questions like: does the theory make sense with my understanding of the world? Is my argument logically consistent? What would be the implication of what I am saying for interventions, other theories, future research, etc.?