Background and Disclaimer
SAFTEr is a package written for R that applies the Sleep, Activity, Fatigue, and Task Effectiveness (SAFTE) model to previously collected sleep data. The SAFTE model is a biomathematical framework that predicts human cognitive performance based on previous sleep patterns.

SAFTEr is based on the original patented model under expired US Patent No. 6,579,233 Entitled: System and Method for Evaluating Task Effectiveness Based on Sleep Pattern. SAFTEr was constructed using the original functions and algorithms provided by and under the supervision of SAFTE model inventor Dr. Steven Hursh.

This R package should not be confused with similarly trademarked product names, such as SAFTE (Fatigue Science) or SAFTE-FAST (Institutes for Behavior Resources, Inc.). SAFTEr is limited to the use of the original patented SAFTE model equations and does not include features specific to the commercial SAFTE-FAST software:

  • scheduling insights
  • Auto-Sleep or automated sleep estimation
  • graphical user interface to interact with the data
  • data importing from scheduling systems
  • batch processing of large data sets
  • a mechanism to phase-shift the model resulting from shift work or transmeridian travel
  • does not consider geographic location or light exposure based on location or time of year
  • does not include derived performance metrics or subjective alertness scores
  • does not include any improvements to the original model made since the time of the patent

The SAFTEr package is intended for use by students, scholars, and scientific researchers as a freely available research tool and is not intended to be used, marketed, or sold as a product or as a service for profit.

The SAFTEr GitHub page can be found at

Email for more information.