Designed and developed at RTI International, SUDAAN® is an internationally recognized statistical software package that specializes in providing efficient and accurate analysis of data from complex studies. SUDAAN is ideal for the proper analysis of data from surveys and experimental studies, since SUDAAN procedures properly account for complex design features, such as correlated observations, clustering, weighting, and stratification. SUDAAN 11, the newest release of SUDAAN, reflects our continued commitment to providing useful statistical tools, which began over 40 years ago.

SUDAAN offers computationally efficient and design-corrected analyses of:

  • Data from complex sample surveys
  • Epidemiological study data
  • Clinical trial data
  • Experiments or observational studies
  • Longitudinal Data

Complex Design Features Supported by SUDAAN

SUDAAN provides estimates that correctly account for complex design features of your study, including:

  • Unequally weighted or unweighted data
  • Stratification
  • With or without replacement designs
  • Multistage and cluster designs
  • Repeated measures
  • General cluster-correlation (e.g., correlation due to multiple measures taken from patients, pups nested within litters, or students nested within schools)
  • Multiply imputed analysis variables

SUDAAN Procedures and Variance Estimation Options

SUDAAN is a single program comprising a family of nine analytic and two new pre-analytic procedures. The two pre-analytic procedures include one procedure that computes weight adjustments using a model-based, weight calibration methodology (WTADJUST) and a second procedure that imputes data using the Cox-Iannacchione Weighted Sequential Hot Deck method (HOTDECK).

All analytic procedures, as well as the new WTADJUST procedure, offer three robust variance estimation methods.

  • Taylor series linearization (GEE for regression models)
  • Jackknife (with or without user-specified replicate weights)
  • Balanced repeated replication (BRR)