Sound educational policy recommendations require valid estimates of causal effects, but observational studies in physics education research sometimes have loosely specified causal hypotheses. The connections between the observational data and the explicit or implicit causal conclusions are sometimes misstated. The link between the causal conclusions reached and the policy recommendations made is also sometimes loose. Causal graphs are used to illustrate these issues in several papers from "Physical Review Physics Education Research." For example, the core causal conclusion of one paper rests entirely on the choice of a causal direction although an unstated plausible alternative gives an exactly equal fit to the data.