SAMPLING
Mortgage QC sampling: random, statistical, and discretionary
A sample is only defensible if the population, method, seed or selection procedure, strata, and final membership are preserved. Changing the file list after seeing results destroys the audit trail.
Random selection
ExactClose ranks each eligible loan with a cryptographic HMAC derived from the locked seed and loan identity. Re-running the same population and seed produces the same order.
Channel stratification
Retail, TPO, and correspondent populations can carry different risks. The default 10% method selects within each channel so a small channel is not lost inside the total population.
Statistical method
The statistical calculator records expected defect rate, precision, confidence factor, finite-population correction, and resulting count. The institution must validate that those parameters match its QC plan and current investor requirements.
Discretionary reviews
Targeted high-risk or adverse-event reviews are valuable but should remain visibly separate from the random sample and its defect-rate denominator.
Last methodology review: July 14, 2026. Source requirements and vendor capabilities change; verify current text before relying on it.