Internal assessment: experimental study design, data analysis and report writing
Internal assessment: experimental study design, data analysis and report writing
The IA is an experimental report in which you replicate or adapt a simple study, analyse the data and write it up. It assesses design, ethical practice, statistical reasoning and clear reporting.
Core rules and concepts
- Design: independent measures or repeated measures; operationalise the IV and DV; control extraneous variables; random allocation where appropriate.
- Ethics: informed consent, no harm, confidentiality, right to withdraw and debriefing.
- Descriptive statistics: mean, median, mode, standard deviation; present with a bar chart and error bars.
- Inferential statistics: Mann–Whitney U for independent groups, Wilcoxon for repeated measures; report the observed value, critical value and p < 0.05.
- Report structure: introduction, method, results, discussion, references and appendices; keep within the word limit.
Worked example
A student tests whether images produce better recall than words using independent groups. Reasoning: independent groups require Mann–Whitney U; the student reports means, standard deviations and U, then compares with the critical value at p < 0.05. If U is not significant, the conclusion must say the difference was not statistically significant - not that there was no difference. The discussion should link back to the background study, acknowledge limitations such as sample size, and suggest a concrete improvement.
Traps that cost marks
- Choosing the wrong inferential test for the design.
- Reporting p > 0.05 as significant, or misreading a one-tailed test.
- Placing raw data in the results section instead of an appendix.
- Failing to operationalise the IV or DV.
- Omitting ethics or exceeding the word limit.