Base Year Calculator (BYC) 

The BYC assembles data from a community’s Point in Time Count (PIT); Housing Inventory Count (HIC); HMIS data; and program budget data to create a “base year” of performance data from which to begin modeling. Outputs of the BYC include a project-by-project evaluation of HMIS data quality and project-level performance measures. The BYC is used to populate the System Performance Predictor (SPP) but is also a useful standalone tool that allows communities to understand the performance of their existing system. Tools and guides for using the BYC are linked below.

“Base Year Calculator User Guide” – UPDATED MAY 2018 – Provides step by step instructions on how to populate and run the BYC.

HIC extraction Instructions – To populate the BYC, data must be extracted from the community’s Housing Inventory Count (HIC) in the HDX system. This document provides instructions for the HIC extraction.

“SWAP Frequently Asked Technical Questions” – FAQs on using the BYC and Budget Tools.

To help illustrate how the BYC works and the types of outputs it produces, the following documents provide sample data for “Anytown USA” on a number of measures.

Once you have reviewed these documents are ready to begin the BYC, use these templates to upload your HIC and HMIS data.


Already have a BYC user name and password? Log in.

Need one? Once you have reviewed our Preparing for SWAP page and read the “Is SWAP Right for Us and Is My Community Ready for SWAP?” document, email us at, subject line “SWAP” for a username and password.