I’m really stuck for a blog topic this week so I thought I’d have a pop at evaluating the methodology of a study by Rahe et al.
Rahe’s study had problems with the method because it was a correlation study. You can’t state that one variable causes the other in a correlation study therefore you can’t draw cause and effect relationships. In this study you have no control of variables and the relationship between the two variables being measured could be explained by a third variable that was not measured. This could mean the conclusions are invalid and therefore the study lacks validity because the level of illness can’t be explained by life changes but by an unidentifiable.This study lacks validity also because the Schedule of Recent Experiences (SRE) contains items that aren’t relevant because of the participants ages (average age of the sailors was 22.3 years.) The perception of each event varies dramatically from one person to the other which also adds to the lack of validity. also, the illness score is not a valid measure as it doesn’t take into account the severity of illness and only reported recorded illness.
Participants had to recall past events which lacks reliability because memory may become distorted therefore inaccurate/unreliable.
Lastly, the sample of 2664 males from the US Navy with average age of 22.3 years is a weak sample. They were young so unlikely to have experienced as many life experiences. The fact they were all males (Androcentric), all American (Ethnocentric) and all sailors makes the sample lack population validity.
They were not aware of the hypothesis therefore no informed consent was given and they were not fully aware of what they were part of and also, no evidence of a right to withdraw which could be down to the military context of the study.