Self-report methods in psychological research

Self-reports serve as a key tool in psychology for gathering data directly from participants. These methods involve asking people about their thoughts, feelings, or behaviours. They are useful for collecting information from large groups.

Questionnaires as a self-report method

Questionnaires consist of a set of written questions distributed to participants, who complete them independently. This approach allows researchers to reach many people at low cost, for example, by posting them or handing them out in public spaces.

Advantages and disadvantages of questionnaires:

• Advantages - They are inexpensive to produce and distribute, and can gather data from a wide audience quickly.
• Disadvantages - Responses might lack depth or accuracy because there is no researcher present to clarify questions. Participants may not understand items, skip them, or fail to return the questionnaire altogether.
• Improving questionnaires - To address potential issues, researchers should design clear, unbiased questions that do not suggest a particular answer - known as leading questions. Testing a preliminary version, called a pilot questionnaire, helps identify and fix problems before full use.

Interviews as a self-report method

Interviews involve direct questioning by a researcher. This method provides greater control over the process but requires more time and resources.

Types of interviews:

• Structured interviews - These use a fixed set of predetermined questions, ensuring consistency across participants.
• Unstructured interviews - Questions start with a basic plan, but the researcher adapts follow-up queries based on the participant's responses. This is common in clinical settings, where deeper exploration of answers is needed.

Advantages and disadvantages of interviews:

• Advantages - Researchers can assess understanding in real time.
• Disadvantages - They are time-intensive.

Closed questions

Closed questions limit responses to predefined options, making them straightforward to quantify. They structure answers into categories set by the researcher.

Types of data from closed questions:

• Nominal data - This type of data fits into distinct categories, such as "yes or no" or "male or female". It allows researchers to count frequencies easily, converting responses into quantitative data.
• Ordinal data - This involves ranking options, often using a scale to measure intensity, such as "strongly agree, agree, neutral, disagree, strongly disagree".
• Advantages - Easy to analyse statistically, as responses can be tallied or averaged.

Hypotheses in psychological research

Before conducting a study, psychologists form a hypothesis.

Defining a hypothesis

A hypothesis is a precise statement that predicts a relationship between two variables. It must be clear enough to test through experimentation or observation.

Experimental or alternative hypothesis

In experimental contexts, the hypothesis is often called the experimental hypothesis or alternative hypothesis. These terms are interchangeable.

Concepts of populations and samples

Key definitions

• Population - This is the entire group sharing certain characteristics.
• Target population - A subset of the broader population that the researcher wants to study and generalise findings to.
• Sample - A smaller group selected from the target population to participate in the study.

Representative and unrepresentative samples

• Representative sample - A representative sample mirrors the key characteristics of the target population. This similarity allows researchers to generalise findings.
• Unrepresentative sample - This does not match the target population's makeup, leading to bias.

Accurate generalisation depends on the sample reflecting the target group; otherwise, conclusions may not apply reliably.

Sampling techniques

Random sampling

• What it is - In random sampling, every member of the target population has an equal chance of selection, similar to a lottery draw.
• How it works - Names or numbers are assigned, then randomly picked, such as drawing from a hat.

Stratified sampling

• What it is - Stratified sampling divides the target population into subgroups (strata) based on key characteristics, then selects proportionally from each.
• How it works - Identify strata like age, gender, or ethnicity. If the population is 60% male and 40% female, a sample of 30 would include 18 males and 12 females.

Opportunity sampling

• What it is - Opportunity sampling selects participants who are readily available at the time of the study.
• How it works - Researchers approach whoever is convenient, such as the first 25 people in a canteen.
• Advantages - Quick and easy to implement.

Volunteer or self-selected sampling

• What it is - In volunteer sampling, participants choose to take part, often in response to an invitation.
• How it works - Researchers advertise for volunteers, such as through newspaper ads, and those who respond form the sample. This was used in studies like Milgram's obedience research.