Chapter 6 non-experimental research

Non-experimental research

Non-experimental research

A research that lacks the manipulation of an independent variable.

3 goals in science

Describe, Predict, & explain

When to use non-experimental research

when these conditions are not met

• no specific research question or hypothesis

• the independent variable cannot be manipulated

• participants cannot be randomly assigned

Types of non-experimental research

• correlational research

• observational research

Correlational research

Research that is non-experimental because it focuses on the statistical relationship between two variables but does not include the manipulation of an independent variable.

• goal is to predict one variable from another

Observational research

Research that is non-experimental because it focuses on recording systemic observations of behavior in a natural or laboratory setting without manipulating anything.

Cross-sectional studies

Studies that involve comparing two or more pre-existing groups of people (e.g., children at different stages of development).

Longitudinal studies

Studies that involve comparing two or more pre-existing groups of people (e.g., children at different stages of development).

Cross-sequential studies

Studies in which researchers follow people in different age groups in a smaller period of time.

Cohort effect

Differences between the groups may reflect the generation that people come from rather than a direct effect of age.

Correlations between quantitative variables are often presented using

scatterplots

Scatterplots

A graph that presents correlations between two quantitative variables, one on the x-axis and one on the y-axis. Scores are plotted at the intersection of the values on each axis.

Pearson’s correlation coefficient

A statistic that measures the strength of a correlation between quantitative variables.

Restriction of range

When one or both variables have a limited range in the sample relative to the population, making the value of the correlation coefficient misleading.

Correlation matrix

Shows the correlation coefficient between pairs of variables in the study.

quantitative research

Research that typically starts with a focused research question or hypothesis, collects a small amount of numerical data from a large number of individuals, describes the resulting data using statistical techniques, and draws general conclusions about some large population. 

qualitative research

Research that begins with a less focused research question, collects large amounts of relatively “unfiltered” data from a relatively small number of individuals, describes data using nonstatistical techniques, such as grounded theory, thematic analysis, critical discourse analysis, or interpretative phenomenological analysis and aims to understand in detail the experience of the research participants.

Mixed-methods research

Research that combines both quantitative and qualitative approaches.

Observational research

Research that is non-experimental because it focuses on recording systemic observations of behavior in a natural or laboratory setting without manipulating anything.