Psychology Research Methods and Data Analysis: Key Concepts and Study Designs

Experiment

Compares data, have independent and dependent variables, can be replicated

Control condition

A level of the IV is an experiment from which the IV itself is absent. Used to compare one or more experimental conditions.

Lab Experiment

The term laboratory refers to the setting (location) in which the experiment takes place. A laboratory is any setting over which the experimenter has a high level of control - for example, they can control the temperature, lighting and noise level.

Field Experiment

Field experiments are good for complex questions because the person is in their natural environment with only a few controlled variables.

Self Report

Participants give information about themselves directly. They are self reporting themselves. Use a questionnaire or an interview.

Interview

A method of self-reporting where participants provide information through verbal questions.

Structured Interview

Questions asked are the same for every participant and the orders are fixed.

Unstructured Interview

Questions asked depend on what the participant says; questions are different for each participant, making it hard to compare data.

Semi-structured Interview

There are some fixed questions and some unstructured questions.

Questionnaire

Questions are presented to participants on paper or online. Participants are either given closed questions with options to select or open-ended questions.

Closed Questions

Questions where participants must select from given options, e.g., What is your gender? Girl or Boy.

Open-ended Questions

Questions that ask participants to be descriptive, e.g., Why do you think we should help people?

Case Study

A detailed investigation of a single instance.

Longitudinal Study

They follow someone for a long period of time.

Observation

Watching human or animal participants.

Naturalistic observation

Being monitored in their own environment.

Controlled observation

A place where the researchers are manipulating the environment.

Unstructured observation

Looking at all the possible behaviors that could happen.

Structured observation

Focus on only one specific behavior, seeing if they are acting a specific way.

Participant observer

They are observing while partaking in the situation being studied.

Unparticipant observer

They are observers while not partaking in the situation being studied.

Convert observation

The role of the observer is not obvious; they are hidden or disguised.

Overt observation

The role of the observer is obvious to the participant.

Correlation

Correlational studies are when they are only comparing variables, but not manipulating them.

Correlation coefficient

A correlation can be expressed numerically as a coefficient, ranging from -1 to +1.

Pearson's r

The correlation coefficient to use when working with continuous variables.

Independent Measures

An experimental design in which a different group of participants is used for each level of the IV (condition).

Matched pair design

For each participant, another person is found who is similar in ways that are important to the experiment.

Repeated measures

An experimental design in which each participant performs in every level of the IV.

Counterbalancing

A way to overcome order effects in a repeated measures design.

ABBA design

A design where half the participants do condition A then B, and another half do B then A.

Random allocation

A way to reduce the effect of confounding variables such as individual differences.

Participants

Individuals put in each level of the IV such that each person has an equal chance of being in any condition.

Order effects

Consequence of participating in a study more than once, which can cause changes that obscure the effect on the DV from the IV since it has nothing to do with the IV.

Practice effect

A situation where participants' performance improves the more they do/experience the experimental task.

Fatigue effect

A situation where participants' performance declines because they experience the experimental task more than once.

Hypothesis

A testable statement that provides a little more detail about the variables being investigated than the aim.

Directional Hypothesis

A hypothesis stating which condition will produce the best, highest scores, or a negative or positive correlation.

Non-Directional Hypothesis

A hypothesis that predicts there will be an effect but not the direction of that effect (does not say increase or decrease).

Null Hypothesis

A hypothesis stating that the difference or correlation could have arisen by chance (no significant pattern).

Independent Variables

The factor under investigation in an experiment that is manipulated to create two or more conditions (levels) expected to be responsible for change in the dependent variables.

Dependent Variables

The factor in an experiment that is measured and is expected to change under the influence of the independent variable.

Operationalization

The process of defining variables in a way that provides consistency and states exact variables.

Extraneous Variables

Anything that is not the independent variable that has the potential to affect the results.

Situational Variables

A confounding variable (an uncontrolled variable) caused by an aspect of the environment, such as the amount of light or noise.

Participant Variables

Individual differences between participants (age, personality, and intelligence) that could affect their behavior in a study and hide or exaggerate differences between levels of the IV.

Population

The group sharing one or more characteristics from which a sample is drawn.

Opportunity Sample

Participants chosen because they are available, such as university students selected because they are present at the university where the research is taking place.

Random Sample

A sampling method where all members of the population are allocated numbers and a fixed amount of these are selected in an unbiased way, such as taking a number from a hat.

Volunteer Sample

Participants invited to participate, for example through advertisement via email or notices, where those who reply become the sample.

Snowball Sample

A non-probability sampling method where currently enrolled research participants help recruit future subjects for a study.

Qualitative data

Descriptive, in-depth results indicating the quality of a psychological characteristic, like a response to open question in self reports or case studies and detailed observation.

Quantitative Data

Numerical results about the amount or quantity of a psychological measure, such as pulse rate or a score on an intelligence test.

Content Validity

The extent to which a psychological instrument accurately and fully reflects the concept being measured.

Ecological Validity

The extent which the findings of research conducted in one situation would generalize to other situations.

Subjectivity

The effect of an individual's personal viewpoint on how they interpret data; interpretation can differ between individual researchers as their viewpoint may be biased.

Objectivity

The impact of an unbiased external viewpoint on how data is interpreted; interpretation is not by an individual's bias.

Demand Characteristics

Features of the experimental situation which give away the aim of the experiment; might make the participant change their behavior to match what they think is gonna happen, affecting validity.

Generalisability

How widely findings apply, e.g., to other settings and populations.

Inter-rater Reliability

The extent to which two researchers interpreting qualitative responses in a questionnaire (or interview) will produce the same records from the same raw data.

Inter-observer reliability

The extent to which two or more observers are observing and recording behavior in the same way.

Test-retest reliability

The consistency of scores for the same person across two or more separate administrations of the same measurement procedure over time; high test-retest reliability suggests the measure provides a stable, reproducible score.

Operational Definitions

Breaking something down numerically; how you are measuring something.