I'd be asking what peer review has been made on the results.
Of course I might be completely wrong in my suspicions, but.....
....researchers depend on funding for their livelihood. They propose all sorts of novel subjects for keeping their jobs going... sorry, for important research.
Often, sampling techniques are suspect, knowledge of the software they use for analysis is poor, and results are made to agree with the original proposal for research, to boost chances of further funding. The great thing is that nobody can actually prove them wrong, easily.
Some years ago when I worked at a university, an expert in the use of some analytical software was demonstrating its use for something called logistic regression. One researcher from a London hospital said - "that's wrong, for our research we have done it this way for years....."
The expert told them that this would produce incorrect results, and proceeded, by using other software for the same purpose, to demonstrate how their results would be flawed.
Afraid to lose face [maybe funds too] the researcher would not agree. They are probably still doing it the wrong way.
In the case of the nuns, I would be highly suspicious if the analysis had been carried out based on a nun's rating of herself.
If someone asked me if I am conscientious, I would say, yes, very. But that is by my standards. Nina might beg to differ. Asking someone of their own view of themselves is simply too subjective.
So we might change the report from saying "The conscientious tend to be more resilient, say researchers" to "Those who believe themselves, rightly or wrongly, to be more conscientious might possibly be more resilient if they are correct in their beliefs, say researchers"
Of course you could say "what do I know?", and you would be perfectly correct.
Well you know another word for concientious could be obsessive! I'm also not sure that being concientious necessarily translates into being "more resilient, and better able to cope with life's difficulties": it could simply be that constantly worrying about how to fulfill your duties might mean that you are concomittently excercising your brain more. Not that I think that "excercising your brain" staves off Alzheimer's per se, but it's quite likely that "concientousness" translates in to other areas of life - not overeating for example.
Having worked in scientific research in private business much of my career, I am with Brucie.
Medical and social sciences research is far too fond of reporting correlations -"people who do that suffer from this". Such results tell us almost nothing unless and until a cause and effect relationship is demonstrated. This usually comes from understanding the mechanism by which "that" results in "this".
Journalists (and many others) do not understand this distinction and stories of correlations are usually dramatic with a strong people focus (as here); accounts of mechanisms are usually unintelligible except by experts. Many research scientists focus on the correlations since this is much easier research and much more likely to result in publishable research reports - and in many professional areas numbers of published papers is key to promotion. The more difficult the research area, the more likely it is that correlation research will be the norm.
AD is a prize example of this. The balance of research is very strongly weighted to correlations. This will continue, I am afraid, until someone discovers the mechanism leading to the disease and (s)he will get a Nobel prize. Would that the Society understood this and put its financial muscle where it is needed instead of wasting it on campaigning for dubious medication. (As I have written in other threads, the Society should push to get understanding as to the mechanism by which anti-cholinesterase inhibitors are so dramatically effective for a few sufferers rather than pushing for everyone to receive the medication when most will see little or no positive effect).