The phrase "a direct correlation among" is correct and usable in written English.
It can be used when discussing the relationship or connection between multiple variables or factors in a study or analysis.
Example: "The research indicated a direct correlation among the levels of education, income, and job satisfaction."
Alternatives: "a direct relationship among" or "a clear link among".
A direct correlation among specific surface area, defect concentration, and maximum sorption capacity has been established, and the sorption kinetics of the graphene for iodine capture was determined.
However, when whole cells are used, it becomes difficult to find a direct correlation among enzyme production, lignin degradation, and sugar yield (Salvachúa et al. 2011; Yamagishi et al. 2011).
In general, we observed a direct correlation among the activities of the different laccase mutants for the three dyes.
We observed a direct correlation among the activities of the clones with violuric acid, acetosyringone and syringaldehyde.
The study showed a direct correlation between feelings of entitlement among white males and homicidal revenge.
Researchers discovered there was a direct correlation between smoking and depression among the 8,556 participants.
In addition to the disappearance of facial hair amongst most global CEOs, U.S. politicians and heads of state, AMI's Dept. of Research & Anthropology cites a direct correlation between the lack of facial hair among the on-air talent on the ESPN sports network -- noted as the "ESPN factor" -- in driving the "facial hair ceiling".
Poor hygiene and sanitation, and high rate of malnutrition among children have a direct correlation with high child mortality and morbidity in the country.
Among those surveyed, there was a direct correlation between religious conviction and an unwillingness to accept the results of empirical scientific investigation.
A direct correlation between phenotype and number of SNCA copies was consistently observed among different studies.
Moreover, the article said, there was a direct correlation between that and both the obesity epidemic and the increasing rates of diabetes among children.
