HEC-SSP is designed for interactive use in a multi-tasking environment. The system is comprised of a graphical user interface (GUI), separate statistical analysis components, data storage and management capabilities, mapping, graphics, and reporting tools.

Over a period of many years, HEC has supported a variety of statistical packages that perform frequency analysis and other statistical computations. Historically, the programs that received the most use within USACE were HEC-FFA (Flood Frequency Analysis) and STATS (Statistical Analysis of Time Series Data). HEC-FFA incorporated Bulletin 17B procedures that were used for flow frequency analysis. The STATS software package was used for statistical analysis of time series data. STATS had the capability of computing monthly and annual maximum, minimum, and mean values along with computing a volume-duration analysis. Two other packages that have received a lot of use within USACE are REGFRQ (Regional Frequency Computation) and MLRP (Multiple Linear Regression Program). REGFRQ performed regional frequency analyses and MLRP was a multiple linear regression analysis tool.

The goal of HEC-SSP is to combine all of the statistical analysis capabilities of HEC-FFA, STATS, REGFRQ and MLRP while advancing the realm of statistical hydrology through state-of-the-art techniques (such as the Expected Moments Algorithm).