Health Psychology. Michael Murray
by suggesting that a drug is better than it actually is. Placebo control conditions have been manipulated to enhance drug effects. The double-blind requirements for RCTs have been broken. Investigators who have received funding from drug companies have written biased or misleading reports. Ghost writers have been employed to write glowing reports. These abuses have led to the wastage of public funds on ineffective drugs and treatments, missed opportunities for improving treatments, and trials being repeated unnecessarily.
The AllTrials movement is campaigning to remove these abuses and to obtain publication of all clinical trials (see www.alltrials.net/).
Repeatability
Reproducibility is one criterion for progress in science. If a study is repeated under similar conditions, then it should be possible to obtain the same findings. However, journal reviewers and editors may not accept a replication or failed replication for publication on the grounds that it is not as ‘newsworthy’ as an original study. In one landmark study, fewer than half of 100 studies published in 2008 in three top psychology journals could be successfully replicated (Open Science Collaboration, 2015). Lack of replication indicates that: (1) Study A’s results may be false, or (2) Study B’s results may be false, or (3) both may be false, or (4) there may be some subtle differences in the way the two studies were conducted – in other words, there were differences in the context. The OSC analysis showed that a low p value was predictive of which studies could be replicated. Twenty of the 32 original studies with a p < 0.001 could be replicated, while only 2 of the 11 papers with a value greater than 0.04 were successfully replicated. The reproducibility of health psychology studies is yet to be fully evaluated.
Replication
Replication is one of the most important research methods in existence. Yet it is hardly used or mentioned in textbooks about research methods. Replication refers to the attempt by an investigator to repeat a study purely to determine whether the original findings can be repeated. Essentially, the researcher wants to know whether the original findings are reliable or whether they have been produced by some combination of chance or spurious factors. If study findings can be replicated, then they can be accepted as reliable and valuable to knowledge and understanding. However, if the findings of a study cannot be replicated, then the findings cannot be accepted as a genuine contribution to knowledge.
Lack of replication has been a bone of contention in many areas of psychology, including health psychology. Traditionally, a low priority has been given to replication of other researchers’ results. Perhaps researchers believe that they will not be perceived as sufficiently creative if they replicate somebody else’s research. In a similar vein, journal editors do not give replications of research – especially failed replications – the same priority as novel findings. This bias towards new positive results, and away from failed replications, produces a major distortion in the academic literature. Lack of replication before publication is the main reason for the so-called ‘Repeatability Crisis’ in psychology and other disciplines.
Single case experimental designs
Single case experimental designs are investigations of a series of experimental manipulations with a single research participant.
Surveys
Surveys are systematic methods for determining how a sample of participants respond to a set of standard questions. They attempt to assess their feelings, attitudes, beliefs or knowledge at one or more times. For example, we may want to know how drug users’ perceptions of themselves and their families differ from those of non-users, or better understand the experiences of patients receiving specific kinds of treatment, how health and social services are perceived by informal carers of people with dementia, Parkinson’s, multiple sclerosis (MS) or other chronic conditions, or learn more about how people recovering from a disease such as coronary heart disease feel about their rehabilitation. The survey method is the method of choice in many of these types of study.
The survey method, whether using interviews, questionnaires, or some combination of the two, is versatile and can be applied equally well to research with individuals, groups, organizations, communities or populations to inform our understanding of a host of very different research issues and questions. Normally, a survey is conducted on a sample of the study population of interest (e.g., people aged 70+, women aged 20–44, teenagers who smoke, carers of people with dementia, etc.). Issues of key importance in conducting a survey are the objective(s), the mode of administration, the method of sampling, the sample size and the preparation of the data for analysis.
As in any research, it is essential to have a clear idea about the objective, why we are doing our study (the theory or policy behind the research), what we are looking for (the research question), where we intend to look (the setting or domain), who will be in the sample (the study sample) and how we use the tools we have at our disposal. The investigator must be cautious that the procedures do not generate any self-fulfilling prophecies. Lack of clarity about the purposes and objectives is one of the main stumbling blocks for the novice investigator to overcome. This is particularly the case when carrying out a survey, especially in a team of investigators who may have varying agendas with regard to the why, what, who, where and how questions that must be answered before the survey can begin.
Modes of administration include face-to-face interview, telephone interview, social media, group self-completion and postal self-completion.
Next, you need to decide who will be the sample for your survey and also where you will carry it out. Which population is your research question about? The sample should represent the study population as closely as possible. In some cases, the sample can consist of the entire study population (e.g., every pupil in a school; every student at a university; every patient in a hospital). More usually, however, the sample is likely to be a random selection of a proportion of the members of a population (e.g., every tenth person in a community, or every fourth patient admitted into a hospital). This method is called simple random sampling (SRS). A variation on SRS is systematic sampling. In this case, the first person in the sampling frame is chosen at random and then every nth person on the list from there on, where n is the sample fraction being used.
In stratified sampling, the population is divided into groups or ‘strata’ and the groups are randomly sampled, but in different proportions so that the overall sample sizes of the groups can be made equal, even though they are not equal in the population (e.g., the 40–59, 60–79 and 80–99 age groups in a community sample, or men and women in a clinical sample). These groups will therefore be equally represented in the data. Other methods include non-probability sampling of six kinds: convenience samples, most similar/dissimilar samples, typical case samples, critical case samples, snowball samples and quota samples.
All such sampling methods are biased; in fact, there is no perfect method of sampling because there will always be a category of people that any sampling method under-represents. In any survey, it is necessary to maximize the proportion of selected people who are recruited. If a large proportion of people refuse to participate, the sample will not represent the population, but will be biased in unknown ways. As a general principle, surveys that recruit at least 70% of those invited to participate are considered representative. The sample size is a key issue. The variability of scores obtained from the sampling diminishes as the sample size increases, so the larger the sample, the more precise will be the estimates of the population scores, but the more the survey will cost.
Systematic Reviews
A systematic review (SR) is a method of integrating the best evidence about an effect or intervention from all relevant and usable primary sources. What counts as relevant and usable is a matter for debate and judgement. Rules and criteria for selecting studies and for extracting data are agreed in advance by those carrying out the review. Publishing these rules and criteria along with the review enables such reviews to be replicable and transparent. Proponents of the SR therefore see it as