Dieted in the year preceding wave 2 b. Can I say for every one female who fails, X number of males will fail? Overweight status and eating patterns among adolescents: Many analysts motivate this approach by assuming that the predicted probability at the mean value of sex is equivalent to the mean of the predicted probabilities for males and females. I recently come across this great article from Decision Science News that gets at this exact question within the context of medical risk.

But for every 10 males who fail, only 4 pass all their classes. In other words, for every 10 females who fail, 20 pass all their classes.

Odds Ratios. You can ignore the part of the header that gives the mean for 0. I have read many papers etc. Sign up for "The Monthly Mean," the newsletter that dares to call itself average, www. Data for this example were drawn from Project EAT Eating and Activity in Teens and Young Adults -II and Project EAT-III, the second and third waves of a longitudinal study designed to examine dietary intake, physical activity, weight control behaviours, weight status and factors associated with these outcomes in young people.

Supplementary data. So at the very least, show what the predicted probabilities are at many values of SAT math, and point out that increasing an SAT math score by 20 points has a very small effect for people whose scores are very low or very high, and a much larger effect for people whose scores are in the middle.

You cannot say for every one female who fails, X number of males will fail. To apply method 1 in practice after performing a logistic regression, the exposure E is set to the possibly counterfactual level e for everyone in the dataset, and the logistic regression coefficients are used to calculate predicted probabilities for everyone at their observed confounder pattern and newly assigned exposure value.

We consider a simple logistic regression with a dichotomous exposure E and a single dichotomous confounder Z , but the model and results obtained below can easily be expanded to include multiple categorical or continuous confounders. Search ADS. Figure 1.

Related articles in Web of Science Google Scholar. When adjusting for dichotomous confounders, marginal standardization is the appropriate method for making inference to the overall source population from which the study sample was drawn, and we hope the syntax provided in the Appendix will facilitate its use available as Supplementary data at IJE online.

University of Washington Biostatistics Working Paper.

Marginal standardization allows inference to the total population, and we observe only slight differences of the prevalence ratio 1. The one thing you have to be careful of, though, is the effect of a predictor on a probability of failing is not constant across all values of the predictor.

Variable settings. The event probability estimates the likelihood of an event occurring, such as drawing an ace from a deck of cards or manufacturing a non-conforming part.

For simplicity, we only consider the probability of the outcome among the unexposed. Method 3 calculates the predicted probability of the outcome by exposure status assuming that every person in the dataset has the mean value of each confounder. For example, the probability of dropping out of school based on sociodemographic information, attendance, and achievement.