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1.1. A case study is an intensive, in-depth investigation of some behaviour or event of interest in an individual, group, organisation or situation. Usually, the 'case' that is the subject of 'study' is a person. It may involve the normal or abnormal behaviour or functioning of an individual, over a short, or long period of time.

1.2. Sometimes a researcher may conduct multiple case studies on a research question and combine the results to look for trends or patterns that permit tentative conclusions.

1.3. Case studies are most often used when large numbers of participants are not available for study; for example, to study individuals with a relatively rare or unusual disorder, problem, ability or characteristic. The case study may involve a combination of data collection methods. For example, an individual may be interviewed at length. Information may also be collected through interviews of family members, friends, teachers or co-workers.


1.4.1. Case studies provide a useful and effective way of obtaining highly detailed information (data and results) on behaviour and mental processes, particularly in relation to rare of unusual disorders or conditions. Their depth of analysis and the richness of the data are commonly described as their main advantage (or 'strength').

1.4.2. In case studies, there is usually no manipulation or control of variables, as with research, conducted under strictly controlled experimental conditions (unless an experiment is used to collect some of the case study data). Consequently, case studies can avoid artificiality and provide a 'snapshot' of the actual or real-life experience of one or more individuals at a particular situation.

1.4.3. Case studies, are, however, not only useful for a 'snapshot'. They can be conducted over a prolonged period, even many years where relevant and practical to do so, and may therefore also be useful for tracking and describing experiences and change over time.

1.4.4. Case studies can also provide insights into how others may think, feel or behave under similar circumstances, especially when information from different case studies on the same topic or research question is compiled and knit together to help identify a general pattern or trend in the results

1.4.5. Another advantage of case studies is that they can be a valuable source of hypotheses for further research or for data to support theory building or challenge a theory’s assumptions.


1.5.1. A major limitation of case studies is that they cannot test a cause–effect relationship as does an experiment.

1.5.2. Their small sample size is another limitation. By their very nature, case studies usually focus on rare or unusual individuals, groups or situations. This means that the sample is often a convenience sample and limited to a size of one. The results for such a sample can usually provide only very tentative and limited support for drawing conclusions.

1.5.3. Because the mental experiences, processes or behaviours of such individuals (or groups) are ‘extraordinary’, they may not reflect typical ways of thinking, feeling or behaving. Therefore, the researcher can never be fully confident that the conclusions drawn from their study are representative of similar instances within the wider population or apply elsewhere over time. This means that a case study usually has poor external validity.

1.5.4. Because of the very detailed and comprehensive data usually obtained, the process of analysing, summarising and reporting these data can be painstaking and time-consuming.

1.5.5. Case studies also have the limitation of being susceptible to biased information from the participants or the researcher. This can influence the accuracy of the information that is obtained and conclusions that may be drawn. For example, case studies usually rely on the individuals under investigation to provide a great deal of the required information. Some participants may not remember clearly what they actually experienced, or they may intentionally change or omit information that they do not wish to reveal for personal reasons.


2.1. An observational study involves collecting data by carefully watching and recording behaviour as it occurs. Psychologists use observational studies to collect data when the behaviour under investigation is clearly visible and can be easily recorded.

2.2. A structured study typically involves operationalising the behaviour of interest and variables that are involved. For example, a researcher observing aggression outside nightclubs in King Street, Melbourne, must define aggression precisely in terms of the variables to be measured and devise a list of the specific behaviours to be observed and recorded. In preparing their observation checklist, the researcher will determine whether, for example, aggression includes shouting or only physical contact and whether an accidental push or shove is to be recorded along with a deliberate push or shove.


3.1. A self-report is the participant’s written or spoken responses to questions, statements or instructions presented by the researcher. For example, a self-report may take the form of answers about study habits before an important exam, to statements in a seven-point rating scale measuring anxiety, or a participant’s diary records kept in response to a researcher’s specific request.

3.2. Questionnaires, interviews and rating scales are the most commonly used self-report measures. All use questions or statements requiring participant responses, but they are often distinguished in terms of how the questions or statements are asked and answered.

3.3. Although questionnaires, interviews and rating scales can be used exclusively or in combination to collect self-reports, they are also commonly used to collect additional data as a part of research studies using other methods, such as experiments, case studies and observational studies.


3.4.1. A questionnaire is a written set of questions designed to draw out self-report information from people on a topic of research interest. It has a structured format and the questions are usually answered by participants in writing, at their own pace and without supervision.

3.4.2. Questionnaires are most often used when responses are required from a large number of participants; for example, as part of a survey. They are an efficient way of collecting self-reports because a researcher can administer the questionnaire via surface mail, over the phone, the internet, or at the same time to a group who are located in the one place, such as in a school or workplace.


3.5.1. An interview usually involves questions that are asked by the researcher with the aim of obtaining self-report information on a topic of research interest. How questions are asked and the categories of response are focused but not necessarily predetermined or fixed.

3.5.2. Interviews are most often conducted with individuals, in a face-to-face meeting or sometimes over the phone, or even through an app like Facetime or Skype. They usually require spoken answers to questions and are rarely used with very large samples as data collection would require a considerable amount of time. Answers may be recorded electronically or in hard copy writing, depending on how the interview is conducted. Unlike questionnaires, which are usually structured, interviews may be structured, unstructured or semi-structured STRUCTURED — a pre-prepared system is used to guide and record observations e.g. a checklist of items to precisely guide what to look for and to record observations e.g. a checklist of items to precisely guide what to look for and to record or exclude In a structured interview, the participant (or ‘interviewee’) is asked specific, predetermined questions in a controlled manner. The most structured interview is when the interviewer simply asks a set of fixed-response questions and records the participant’s answers. The interviewer follows a script and the questions are read out from a list in a neutral manner with no comments or cues. This is done to ensure that all participants are treated in the same way and thereby help maintain standardised procedures. SEMI-STRUCTURED— a part of the study involves using a predetermined format. In a semi-structured interview, the researcher uses an interview guide listing a set of issues to be explored. The researcher aims to cover all issues but there are no set questions to be asked. As with the unstructured interview, there is a spontaneous generation of questions through interaction with the participant UNSTRUCTURED— observations are made without a predetermined format. In an unstructured interview, the researcher has an overall aim of what data should be collected, but the interview is driven by the participant and there is a spontaneous generation of questions in the natural flow of interaction with the participant. There is also freedom of discussion and interaction between interviewer and participant. For example, the interviewer may ask additional questions to follow up on a participant’s response. This means that questions asked in an unstructured interview can vary widely from participant to participant A goal of unstructured interviews is to allow people to describe their thoughts, feelings and behaviour in their own way using their own words and to give more or less emphasis to relevant issues. This is different from structured interviews (and questionnaires) for which participants have to use the questioner’s terms and concepts to describe how they think, feel or behave. However, this also means that the data collected through unstructured interviews is much more detailed, has far less structure, and is therefore more difficult to analyse, summarise and describe for reporting purposes.


3.6.1. A rating scale uses fixed-response questions or statements for which participants rank (‘rate’) each item by selecting from a number of choices. They may be used to collect data on any behaviour or mental process about which a participant can provide information.

3.6.2. Responses are typically assigned numerical values that enable answers to be quantified (converted to numbers) for summary, analysis and interpretation. The rating scale is not unlike a multiple choice test, but the answer options represent levels or degrees of a particular characteristic. However, there is no correct answer for a rating scale item, other than what the participant decides to give.


3.7.1. Self-report measures such as questionnaires, interviews and rating scales are widely regarded as useful techniques for collecting any type of data on how people think, feel and behave. In particular, they can be an efficient means of collecting data from a large number of people in a relatively short period of time.

3.7.2. They also have the advantages of making it relatively easy to compare responses among participants and to replicate a study, especially when structured measures are used.

3.7.3. By guaranteeing anonymity, questionnaires in particular, provide a means of collecting self-report data on ‘sensitive’ or controversial topics that many people are not willing to disclose publicly, such as in an unstructured oral interview.


3.8.1. However, like other self- reports, they rely on the assumptions that people are actually willing to answer all questions and that they will give accurate answers.

3.8.2. Another limitation of self-reports is social desirability. People may intentionally give false or misleading answers to create a favourable impression of themselves.