To familiarise yourself with the study design concepts central to this course, it is recommended that you take the following steps:
1. Look up any terms in the figure that you’re unsure about in the accordion on this page. The same definitions are provided in the course glossary. Definitions are available for both the types and sub-types of research design. So, for example, there is an entry for ‘longitudinal studies’ and each sub-type of longitudinal study: ‘trend studies’, ‘time-series studies’, ‘panel designs’, and ‘cohort studies’.
2. Review the definitions for ‘randomised controlled trials’, ‘individually-randomised controlled trials’, and ‘cluster-randomised controlled trials’, as Assessment 2 is focused on these study types.
3. Read the remainder of this page, which explains the axes of Figure 2.1—levels of internal and external validity.
4. Complete the readings on this page, which focus on:
o various types of validity, and their relationship to ‘reliability’
o concepts analogous to validity and reliability in qualitative research.
5. Reflect on the internal and external validity in the last psychological study you were asked to write a scientific report on as an assessment:
o Of the study types in Figure 2.1, which one was the study closest to?
o Does Figure 2.1 accurately capture the balance the study achieved between internal and external validity?
o Was the internal validity of the study compromised due to confounds?
6. Share your reflection on the General Discussion Board, prompting instructors and other students to share some of their experiences.
7. Work through the ‘Check Your Understanding’ formative quiz on the next page.
Notably, understanding internal validity is critical to completing Assessment 2: Report — Formally Assessing the Quality of a Single Study, in which you will assess the quality of a randomised controlled trial based on the extent to which the study design facilitates internal validity.
