- Practical Evaluation
- + Replicable as it is permanent document = repeat to get same results.
- - Subjective researchers differing ideas about what is positive or negative.
- + Study behaviour retrospectively
- + Do not have to consider ethics = no pps. used.
- - No experimental control = difficult to establish cause and effect.
- - Low validity as secondary data may be out of date.
- =-Only 2 articles used, low generalise.