Fingerprint based system seems like an interesting choice. Don't these people do a lot of manual labor that scratches fingers? I sometimes have identifying trouble myself due to finger damage and I sit in an office.
We're testing a few identification methods in addition to fingerprints, including cards with QR codes, name lookup, and family lookup. For fingerprints, we're using an algorithm created by Simprints out of Cambridge that's specifically for low-income settings where there's a lot of manual labor. Glancing at our data, it seems like so far we're getting good reads on more than 75% of scans. Hopefully we can improve that with some optimization. Another challenge with fingerprints is they don't work for kids under six, so regardless you need a backup identification method like a card.
