Research methods Key Terms

Independent Variable

The variable that the researcher manipulates or varies to observe its effect on the dependent variable.

Dependent Variable

The outcome variable that is measured to assess the effect of changes in the independent variable.

Participant Observation

A method where the researcher actively engages with the group being studied, often taking part in the activities.

Non‑Participant Observation

A method where the researcher observes the group from a detached position without direct involvement.

Reliability

The consistency of a measurement; a reliable instrument yields similar results under consistent conditions.

Validity

The extent to which an instrument measures what it purports to measure.

Correlation

A statistical relationship between two variables, measured by a correlation coefficient, indicating how one variable changes as the other changes.

Experiment

A study in which the researcher manipulates an independent variable, controls extraneous variables, and randomly assigns participants to conditions to test causal relationships.

Content analysis

A research method that systematically codes and quantifies elements within qualitative data to identify patterns and relationships.

Case study

An intensive, contextual examination of a single case or a small number of cases using multiple data sources to generate detailed insights.

Aim

A broad statement of the research purpose, outlining what the researcher intends to investigate.

Directional hypothesis

A testable prediction that specifies the direction of the relationship between variables.

Random sampling

A probability sampling method where every individual in the population has an equal chance of being selected, ensuring a representative sample.

Opportunity sampling

A non‑probability sampling method that selects participants based on their easy accessibility to the researcher, often leading to bias.

Reliability

The degree to which a measurement instrument yields consistent results across repeated administrations or across items within the instrument.

Validity

The extent to which an instrument measures what it is intended to measure, reflecting the accuracy of the construct assessment.

Objectivity

The requirement that research be conducted and reported in a way that allows independent evaluation, minimizing personal bias.

Hypothesis Testing

The process of using statistical analysis to determine whether data support a specific, falsifiable prediction.

Quantitative data

Data that are expressed numerically and can be subjected to statistical analysis.

Qualitative data

Data that are descriptive, non‑numerical, and capture meanings, experiences or observations.

Primary data

Information gathered directly by the researcher for a specific study, typically through experiments, surveys or observations.

Meta‑analysis

A quantitative method that aggregates effect sizes from several studies to produce a single, overall estimate of an effect.

Mean

The arithmetic average of a set of numbers, calculated by summing all values and dividing by the number of observations.

Median

The middle value in an ordered data set, with an equal number of observations above and below it.

Range

The numerical difference between the maximum and minimum values in a data set.

Standard Deviation

The square root of the average of the squared deviations from the mean, indicating the typical distance of data points from the mean.

Percentage

A proportion expressed as a fraction of 100, calculated as (part ÷ whole) × 100.

Correlation coefficient

A statistical measure (e.g., Pearson’s r) that quantifies the strength and direction of a linear relationship between two continuous variables.

Central tendency

Measures that describe the centre of a distribution, such as the mean, median and mode.

Variability

Measures that describe the spread of a distribution, such as the range, inter‑quartile range and standard deviation.