Analyze Cash Forecast Errors by Cause

A cash forecast can reach the correct closing balance for the wrong reasons. Lower receipts and lower payments may offset each other, hiding weak assumptions in both schedules. Evaluate receipts and payments separately before assessing the closing balance. Define the sign of every variance so a positive payment variance is not mistakenly described as more cash available.

Build a signed variance bridge

Assume a hypothetical week begins with $8,000. Forecast receipts are $20,000 and forecast payments are $18,000, giving $10,000 expected closing cash. Actual receipts are $17,000 and actual payments are $16,000, leaving $9,000. Define each flow variance as actual minus forecast. Receipt variance is −$3,000 and payment variance is −$2,000.

The lower payments partly offset the receipt shortfall: −$3,000 − (−$2,000) = −$1,000. That is a cash bridge, not a statement that the payment reduction was a lasting saving. A supplier payment moved into next week can improve this week's closing balance while leaving the overall obligation unchanged.

Compare bias with the size of misses

Suppose receipt errors across three weeks are −$3,000, +$3,000, and $0. Their signed average is zero, but their mean absolute error is ($3,000 + $3,000 + $0) divided by three, or $2,000 per week. The zero signed average shows offsetting errors; it does not establish accurate timing. The two nonzero errors could represent one receipt arriving a week later than expected.

If actual receipts across those weeks total $60,000, absolute errors totaling $6,000 represent 10% of actual receipts under that chosen denominator. Label it explicitly. A percentage based on forecast receipts answers a different question. When the selected total denominator is zero, the percentage is undefined; report dollar errors rather than replacing the result with zero.

Use dollar amounts alongside percentages to decide which misses need investigation. A $200 payment excess against a $100 payment forecast is a 200% error, while the same excess against a $20,000 forecast is 1%. The cash difference is identical. A large percentage on a small base should not automatically outrank a larger dollar shortfall elsewhere in the schedule.

Preserve forecast versions and classify causes

Save the forecast that existed before the week began. Updating it after actual receipts arrive and then measuring accuracy against the revised version removes the evidence of the miss. Match errors to invoices and payments, distinguishing timing shifts, changed amounts, omitted items, duplicates, and incorrect opening balances.

For a timing shift, show the linked opposite effect in the later week instead of labeling both weeks as unrelated performance failures. For an amount change, update the remaining forecast without inventing a later catch-up receipt. This method does not assign blame or prescribe a universal accuracy target. It helps identify whether the next improvement belongs in collection dates, vendor scheduling, scope assumptions, or the process for recording known commitments.

Method references: OpenStax: Standard Costs and Variances. Accessed October 22, 2026. All dollar figures are hypothetical worked examples.