Applying the foregoing sample sizes, PG&E randomly extracts customer billing and payment data from PG&E's customer information system. A PC-based software application is then used to select customer billing dates and billing amounts for a specific calendar month.

Program logic enables the application to search the record for an exact match between the amount billed and a subsequent payment amount. Where an exact match is found, the number of days between the billing date and payment date is recorded along with the payment amount.