Research involving 1,173 PhD students shows that those with higher conscientiousness are more productive

The study that was recently published in the Journal of Informetrics involving 1173 Ph.D. students in Sweden found that the average number of publications seem to increase with conscientiousness similar over all research areas…”.

Does this mean that prior to accepting a Ph.D. student a supervisor should ask him (or her) to take a psychological test in order to assess the personality trait of conscientiousness?

But in that case, what should we think of the study by researchers from the United Kingdom, the Netherlands and Sweden, which correlated schizophrenia and the number of Nobel Prizes?

PS – The aforementioned study noticed that the general rule showed a (strange) exception for Ph.D students of Engineering and Technology ! But why is it that the productivity of young researchers in these areas does not depend on their conscientiousness levels?