Dear Kenneth,

I believe it is not mandatory to have an independent outcome assessor in case studies, although it "should" be so, per se.

I also wanted to add that till today, RCTs have predominantly emphasised the efficacy of the interventions (explanatory trials) rather than the effectiveness (pragmatic trials), promoting finding causal associations under strict conditions (which I am not criticising, BTW!). Simultaneously, case studies have been a convenient venue for researchers to focus on the effectiveness of interventions (and, of course, the feasibility). In neither scenario, an independent outcome assessor is mandatory for case studies.

Be that as it may, most principal investigators do not analyse the data in medicine themselves, especially in case studies. The outcome assessors will automatically be their students and residents (in hospitals) assessing the outcomes! And, of course, the principal investigators will usually re-check the results before publishing.

To a degree this will be determined by the tools you are using to evaluate outcome. If the tools have high inter-observer reliability then it would be ideal to have an independent observer

Hi,

When the outcome measurement can be subjectively administered and scores are locked once submitted then this observer bias can be decreased.

In neuropsychological tests, bias can be mostly reduced as it can be administered and locked.

I don't think so Outcome assessor are usually not independent of investigator .but non feasibility part and adverse effects should me minimal while doing case study