Some dance to remember; some dance to forget... or drink in this case?

Interesting article 

https://www.ncbi.nlm.nih.gov/pubmed/28391598

I am fascinated by the finding that low parenting predicts LESS alcohol use in the second group of adolescent girls (p=0.057, almost). Are they self-disciplined precocious occasional drinkers? Is low parenting an indicator for something else for this group? Also noticed the correlation between alcohol use and low parenting is negative at baseline for the second group. They are definitely a special group.

I think the authors raised an important point. We often look at the average assuming cases and effect estimates are homogeneous, but more often they are not. 

My thoughts about Jim's question on whether it is worth the while to publish cross-sectional evidence on parenting-alcohol relationship: it would come down to the assumptions. If it is safe to assume the relationship is a positive feedback loop, then yes. If it is a one-way positive or negative relationship, then yes. Would provide initial estimates for future longitudinal studies. If it is a two-way negative relationship or a mixture of positive and negative relationship, then probably no, because it becomes complicated very quickly depending on when kids are assessed in a cross-sectional survey. 

But again, that is population average. Does it apply to everyone? Maybe not. In addition, there may be unobserved heterogeneity in the background. Parental drinking, peer affiliation, number of kids in the household, neighborhood environment... 

Comments from Jim:

Chicken and egg problem: What if drug use causes parents to relax their supervision and monitoring?There is a quite rational decision in epidemiology to start with relatively inexpensive and logistically feasible study designs, such as case-control research, before moving on to the more expensive prospective two-wave or longitudinal multi-wave designs that can throw more light on issues such as uncertain temporal sequencing. (Here, some epidemiologists would turn to the within-field jargon term of 'reverse causality,' but let me again warn that communication across disciplinary boundaries is far more important than any display of group membership as represented by use of within-field jargon terms. 'Uncertainty about temporal sequencing' is apt to serve well in a public forum or research article, whereas epidemiology 'bull sessions' might be appropriate venues for the within-field jargon of 'reverse causation' and the like.)

This new contribution is a very interesting longitudinal multi-wave study that deserves attention because it has a capacity, within the limits of its assumptions, to estimate the degree to which drinking might cause parents to back off and relax their supervision and monitoring behaviors. The assumptions, both conceptual and methodological, should be studied with care, and after you consider the evidence, ask yourself whether it was a mistake for journals to publish the early articles with no more than cross-sectional or two-wave study data on the monitoring hypothesis.

If interesting comments are provoked, I will leave a later comment to tell you what I  think.