- Sample-size calculations for the Cox proportional hazards regression model with nonbinary covariatesF Y Hsieh
CSPCC, Department of Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
Control Clin Trials 21:552-60. 2000..This paper also provides a variance inflation factor together with simulations for adjustment of sample size when additional covariates are included in the model. Control Clin Trials 2000;21:552-560..
- An overview of variance inflation factors for sample-size calculationF Y Hsieh
Department of Veterans Affairs, Palo Alto Health Care System 151 K, Palo Alto, CA 94304, USA
Eval Health Prof 26:239-57. 2003..To design a study, researchers can apply these design effects, also known as variance inflation factors to adjust the power or sample size calculated from a two-group parallel design using standard formulas and software...