Logistic RegressionLogistic Regression

Bandit Thinkhamrop, PhD. (Statistics)Bandit Thinkhamrop, PhD. (Statistics)Department of Biostatistics and DemographyDepartment of Biostatistics and Demography

Faculty of Public Health, Khon Kaen UniversityFaculty of Public Health, Khon Kaen University

Begin at the conclusionBegin at the conclusion

7

Begin at the conclusionBegin at the conclusion

Type of the study outcome: Key for selecting Type of the study outcome: Key for selecting appropriate statistical methodsappropriate statistical methods

• Study outcomeStudy outcome• Dependent variable or response variableDependent variable or response variable• Focus on primary study outcome if there are moreFocus on primary study outcome if there are more

• Type of the study outcomeType of the study outcome• ContinuousContinuous• Categorical (dichotomous, polytomous, ordinal)Categorical (dichotomous, polytomous, ordinal)• Numerical (Poisson) countNumerical (Poisson) count• Event-free durationEvent-free duration

The outcome determine statisticsThe outcome determine statistics

Continuous Categorical Count Survival

MeanMedian

Proportion(PrevalenceOrRisk)

Rate per “space”

Median survivalRisk of events at T(t)

Linear Reg. Logistic Reg. Poisson Reg. Cox Reg.

Statistics quantify errors for judgmentsStatistics quantify errors for judgmentsParameter estimation

[95%CI]

Hypothesis testing[P-value]

Parameter estimation[95%CI]

Hypothesis testing[P-value]

Back to the conclusionBack to the conclusion

Continuous Categorical Count Survival

Magnitude of effect95% CIP-value

Magnitude of effect95% CIP-value

MeanMedian

Proportion(Prevalence or Risk)

Rate per “space”

Median survivalRisk of events at T(t)

Answer the research questionbased on lower or upper limit of the CI

Appropriate statistical methods

Begin at the wrong destinationBegin at the wrong destination

Forest plotForest plot

Another “wrong scale” forest plotAnother “wrong scale” forest plot

Receiver Operating Characteristic CureReceiver Operating Characteristic Cure

Optimal cut-off point Optimal cut-off point

Diagnostic performanceDiagnostic performance