The Department of Surgery Statistical Analysis/Research Programming Core provides faculty, researchers, and residents with comprehensive statistical support for their research activities.
Study Design and Grant Application
We assist with study design and grant application through selection of outcome variables, statistical analysis planning, power analysis and sample size calculation, and random assignment of treatment conditions. It is strongly recommended that the investigators include biostatisticians at the beginning or early stage of their studies to ensure optimal study design and an appropriate data analysis plan.
Statistical Analysis and Results Interpretation
We perform research hypothesis testing and data analysis using a variety of statistical methods. The choice of statistical method depends on the study design, type of outcome measure, and research question. The statistical methods we are able to apply include (but are not limited to):
• Analysis of Variance (ANOVA)
• Linear Regression
• Logistic Regression
• Generalized Linear Model
• Survival Analysis (Kaplan-Meier, log-rank test, Cox proportional hazards models)
• Nonparametric Statistics
• Longitudinal Data Analysis
• Multilevel Modeling
• Structural Equation Modeling
• Data Mining
• Machine Learning
• Model Selection and Variable Selection
We also interpret the analysis results and translate statistical significance to clinical implications.
Evaluation of Measurement
We evaluate psychometric properties of measurement instruments including survey questionnaires. We can assess reliability, validity, and factor structure of the instruments, and perform item and test analysis.
Database Management and Preparation
We work closely with the investigators in Wisconsin Surgical Outcomes Research Program (WiSOR) on research projects that utilize large national health outcome databases. We provide database management, maintenance, patient cohort extraction, and analytic data set preparation. Visit the WiSOR page on the Department of Surgery Intranet for a list of the outcomes databases available.
Manuscript and Presentation Assistance
We can provide feedback for peer-reviewed publications and oral and poster conference presentations. Our collaboration and contribution can include the description of statistical analysis methods, generation of results summary tables and figures, and reviewing and editing of manuscripts, abstracts, and presentations.
Consultation and Training
We provide consultation and training on study design, data creation and management (for both in house and large national databases), statistical analysis methods, and statistical software programs (including SASTM, SQL, Stata, R, SPSS, and Matlab).