Calculate impression count, discrepancy rate, or number of discrepancies in impressions by entering any two values and finding the missing one.
Discrepancy Rate Formula
The discrepancy rate measures the percentage of impressions that have a discrepancy. The calculator uses this main formula:
DR = (ND / IC) * 100
- DR = Discrepancy rate, as a percentage
- ND = Number of discrepancies in impressions
- IC = Impression count
If you leave the discrepancy rate blank, the calculator solves for it using the formula above.
If you leave the impression count blank, the calculator rearranges the formula:
IC = (ND / DR) * 100
If you leave the number of discrepancies blank, the calculator uses:
ND = (IC * DR) / 100
The calculator is set up so you enter any two values and leave the third value empty. It then calculates the missing value. Impression count cannot be zero when solving for discrepancy rate, and discrepancy rate cannot be zero when solving for impression count.
Discrepancy Rate Interpretation
The meaning of a discrepancy rate depends on the system, campaign, reporting window, and measurement method. The table below gives a general way to read the result.
| Discrepancy Rate | General Interpretation | What to Check |
|---|---|---|
| 0% to 2% | Low discrepancy | Usually within normal reporting variation |
| 2% to 5% | Moderate discrepancy | Check timing, filters, and reporting settings |
| 5% to 10% | High discrepancy | Review tracking setup and data source differences |
| Above 10% | Very high discrepancy | Investigate measurement errors, missing tags, or mismatched definitions |
Common Input Relationships
| If You Know | Leave Blank | Calculator Solves |
|---|---|---|
| Impression count and number of discrepancies | Discrepancy rate | The percentage of impressions with discrepancies |
| Discrepancy rate and number of discrepancies | Impression count | The total impressions implied by those discrepancies |
| Impression count and discrepancy rate | Number of discrepancies | The expected count of discrepant impressions |
Example Problems
Example 1: Calculate discrepancy rate
You have 50,000 impressions and 1,250 discrepancies.
DR = (1250 / 50000) * 100
DR = 2.5%
The discrepancy rate is 2.50%.
Example 2: Calculate number of discrepancies
You have 80,000 impressions and a discrepancy rate of 3.25%.
ND = (80000 * 3.25) / 100
ND = 2600
The number of discrepancies is 2,600.
FAQ
What is a discrepancy rate?
A discrepancy rate is the percentage difference between a total impression count and the number of impressions that do not match the expected count or another reporting source. In this calculator, it is calculated as the number of discrepancies divided by the total impression count, then multiplied by 100.
Why can a discrepancy rate happen?
Discrepancies can happen because of reporting delays, different counting methods, blocked tracking, filters, time zone differences, duplicate removal, or missing impression data. A small discrepancy is often normal, but a high discrepancy usually needs review.
Can the number of discrepancies be a decimal?
The calculator may return a decimal because it uses the exact percentage formula. In real impression reporting, discrepancies are usually whole counts. If the result is a count of impressions, you may need to round it based on how your reporting system handles impression totals.
