Diagnosing and revising logistic regression models

Abstract

PurposeThis study aims to apply a systematic statistical approach, including several plot indexes, to diagnose the goodness of fit of a logistic regression model, and then to detect the outliers and influential observations of the data from experimental data.Design/methodology/approachThe proposed statistical approach is applied to analyze some experimental data on internal solitary wave propagation.FindingsA suitable logistic regression model in which the relationship between the response variable and the explanatory variables is found. The problem of multicollinearity is tested. It was found that certain observations would not have the problem of multicollinearity. The P‐values for both the Pearson and deviance χ2 tests are greater than 0.05. However, the Pearson χ2 value is larger than the degrees of freedom. This finding indicates that although this model fits the data, it has a slight overdispersion. After three outliers and influential observations (cases 11, 27, and 49) are removed from the data, and the remaining observations are refitted the goodness‐of‐fit of the revised model to the data is improved.Practical implicationsA comparison of the four predictive powers: R2, max‐rescaled R2, the Somers' D, and the concordance index c, shows that the revised model has better predictive abilities than the original model.Originality/valueThe goodness‐of‐fit and prediction ability of the revised logistic regression model are more appropriate than those of the original model.

Logistic Regression With Machine Learning Sheds Light on the Problematic Sexual Behavior Phenotype

“…Outliers were removed from the logistic regression (n = 47, with 8 categorized as “yes” to having PSB; Supplemental Digital Content, Supplementary Fig. 2, http://links.lww.com/JAM/A375) if their Pearson standardized residual had an absolute value of more than 2, 34 or Hosmer-Lemeshow ∆ trueβ̂ more than 4 35 . The following variables were associated with PSB: OCD, ASRS, IAT, a family history of PSB, SA-SAPAS, childhood trauma, RCBS, and gender (men) (odd ratios and P values are provided in Fig.…”