Quick answer: Compare the estimate's cost assumptions with the completed job using the same scope and cost categories. Separate scope changes from estimating errors, then record why labor, materials or other costs differed before updating your rates.

A job can exceed its estimate because the scope grew, a quantity was wrong, access was harder than expected or a supplier cost changed. Those causes need different fixes. A single “bad job” label does not tell the next estimate what to do differently.

Compare costs rather than mismatched totals

Keep customer selling price separate from the estimated cost of doing the work. Comparing actual material cost with a marked-up selling line creates a misleading variance. Use the same cost basis on both sides.

For changed work, identify the original scope and the approved additions separately. Otherwise the review may blame the original estimate for costs belonging to a later decision.

Use a compact variance worksheet

Job-cost review fields
Category	Estimated basis	Actual record	Reason
Labor	Hours and cost rate	Recorded hours on the same scope	Production, access or added work
Materials	Quantity and supplier price	Purchases assigned to the job	Selection, waste or price change
Subcontractors	Reviewed quote	Cost for the agreed scope	Excluded or changed work
Equipment and disposal	Job-specific allowance	Assigned invoices or records	Duration, quantity or mobilization

Use your accounting process for cost assignment and appropriate professional input. This worksheet is an operational review, not a tax or bookkeeping rule.

A fictional variance example

Illustrative example: A scope was estimated at 24 labor hours and used 30 hours. The difference is 6 hours. Before changing the production rate, identify whether those hours were spent on the original work, an approved addition, waiting for access or rework.

If 4 hours belong to added work, the original-scope comparison is different from a simple 6-hour overrun. Keep the supporting notes rather than smoothing every difference into the next job's price.

Choose the correction that matches the cause

Missing task: Improve the scope checklist.
Wrong quantity: Improve measurement and unit verification.
Repeated production difference: Review the labor assumption across comparable jobs.
Supplier price change: Update the price source and date.
Unusual condition: Define when that condition needs separate pricing.
Customer change: Improve the change record and approval process.

One unusual job should not automatically rewrite every company rate. Look for a repeated pattern in similar work, and preserve the reason behind each update.

Bring the finding back to the next estimate

Assign the corrective action to a person. Update the scope template, rate entry or handoff rule, then check whether the next comparable job includes the change. A review has little value if the lesson remains in a conversation nobody records.

Keep the original estimate version. Changing today's rate library should not make last month's proposal appear to have used a different assumption.

SnapDamage can preserve the project documentation and reviewed estimate used as the starting point. Actual costs may live in your accounting or job records; this guide does not claim an automatic job-costing integration. Use the rate-library template and change record.

Frequently asked questions

Is every overrun an estimating failure?

No. Separate the original scope from changes and other causes before deciding what the estimate got wrong.

Should I compare gross margin across jobs?

Use a consistent cost definition and scope. A margin figure is difficult to interpret when the underlying categories differ.

How often should I review costs?

Review when the job's records are complete enough to explain the differences and while the details are still available. Set a cadence your business can maintain.