I'm running a logistic regression (N = 15000) and the percentage accuracy in classification (sensitivity) of the model with predictors included = 0 (the SAME as the constant model without predictors). Meanwhile the specificity remains unchanged from the constant model to the model with predictors (both 100%).
I start with a rather high overall success rate from the constant (95.2%). Maybe that is too high to start and suggests a problem?
But the output of the logistic regression seems to suggest that my added predictor variables (gender (dichotomous); age (continuous); country of origin (dichotomous dummy coded)) have no influence on membership to the group. Does this simply mean the model is without value and I shouldn't use any of the other outcomes from it?