One set of numbers everyone trusts needs shared definitions, source evidence and calculations that reports actually reuse. Establishing this single source of truth, or SSOT, begins with a concrete disagreement. Determine what the reports mean, resolve the records behind their differences and maintain the accepted rule with a clear reporting date and correction process.
Employee headcount, filled positions and available staff may all appear as a workforce total. When three departments take those numbers to the same meeting, they can look like conflicting accounts of the same situation.
First decide which question the meeting needs answered. That gives the reconciliation a purpose: explain that measure and make its calculation repeatable.
Agree what the number means
Reports agree only when they count the same thing under the same conditions. Set the unit, population and date before comparing totals. An assignment active at any time in a month differs from an employee present at month end.
A person with two assignments illustrates why the unit matters. A row count can include both assignments; a distinct-person count includes the employee once. Microsoft's modeling guidance describes this issue through grain, the unit represented by a row.
Get approval for the business meaning before adopting the calculation. Where both measures serve a purpose, name them distinctly. The report should help readers select the appropriate one.
Trace the records behind the difference
A disputed total becomes easier to resolve when the team can identify which records differ. Compare the populations for one period. Start with the people or transactions included in one report and absent from the other.
Inspect the joins that produced them. An unmatched identifier can remove a record; two matching related records can multiply it. Neither error necessarily makes the total look implausible.
Clarify which system establishes each fact. Employment status may belong to the HR record and assigned work to the scheduling record. Their relationship requires matching identifiers and dates.
Preserve the explanation when correcting the query. A manual adjustment can fix this month's total while leaving next month's problem unchanged. Encoding the agreed treatment lets the report repeat it and allows another reviewer to understand why it exists.
Make reporting time explicit
A historical number needs both a reporting date and a policy for later corrections. A transfer entered in October can apply to September. A new calculation of September may therefore differ from the report originally issued.
Label the corrected view and retain the original pack. One describes the latest account of the period; the other records what readers received before the correction. Both have a useful role.
Reproduction requires evidence from the original run. Preserve the relevant extract, effective dates, filters and calculation version, or an equivalent retained dataset.
Databricks' history guidance distinguishes time travel from long-term archival storage. Set the retention approach around how long reports must be explained. The availability of a history feature does not by itself satisfy that requirement.
Test the calculation against known cases
Agreement becomes useful when the calculation reproduces the cases its owners understand. Include an ordinary employee, a person with two assignments, a transfer and a late correction. Each tests a different part of the definition.
Inspect the records behind a changed total. If the new result removes two repeated assignments, show those assignments and the rule that removed them. A smaller number alone does not demonstrate a better calculation.
Run the old and proposed reports for the same period before replacing the accepted output. Record unresolved differences and their effect. The owners can then approve a change with an explanation of what it fixes and what remains open.
This review also identifies training needs. If users have treated “employees” and “available staff” as interchangeable, the new report needs to make their difference easy to understand.
Reuse the accepted definition
The accepted measure should supply the reports and questions that claim to use it. Maintain its logic in a business view and connect the required outputs. Check that an export has not retained an older formula independently.
Readers still need to see the scope of a number. A regional manager's permitted subset can differ from the company-wide total. Reporting dates and filters can produce other legitimate differences.
For an AI question, inspect which definition the answer selected and the query it ran. An ambiguous term needs clarification before a figure can be interpreted. The model should use the agreed meaning when it constructs the query.
A scheduled check can reuse the measure too. Define the comparison, conditions for review and responsible recipient. The resulting explanation then refers to a calculation the business already understands.
Maintain the agreement after rollout
A shared measure needs a way to change without creating new competing versions. New categories or reorganizations can require a revised definition. Record its approval and test the effect on existing outputs before release.
Databasin connects source preparation and definitions with reports, rollout and support. That work follows the answer into use, including changes to the data or business process afterwards.
Begin with a recurring decision whose records and recipients are known. The first release can test both the calculation and whether people use it as intended. It establishes a method for the next measure without assuming that the same definition applies everywhere.
Example: reconciling a monthly headcount
In this illustrative September review, the owners reconcile assignments, employees and availability before recording a late correction.
| Check | Finding | Treatment and result |
|---|---|---|
| Unit, 30 September | Two of 102 assignments are additional assignments for people already included. | The distinct employee count is 100. |
| Availability | Three employees are on leave. | Retain headcount of 100 and report 97 available staff separately. |
| Department | Two transfers are effective from 1 October. | Use the September departments for the month-end count. |
| Correction, 3 October | A termination arrives effective 30 September. | Retain the issued count of 100 and identify the revised count of 99. |
Each figure now has a defined purpose. The late correction is distinguishable from the earlier differences in what the reports counted.
Checks for a shared measure
- Select the disagreementIdentify the decision waiting on conflicting figures. Determine whether the reports answer the same question and which measure the decision needs.
- Approve the definitionEstablish the unit, population, reporting date and exclusions. Name the owner of the meaning and the person maintaining its calculation.
- Explain the recordsCompare the included records and resolve each difference. Encode the treatment with a test that makes its effect visible.
- Preserve the report versionRetain the evidence behind the issued figure. Specify how later corrections are identified and how their effect is explained to readers.
- Reuse the calculationConnect relevant reports and questions to the maintained measure. Keep scope, reporting period and refresh information beside the result.
Sources
Microsoft, Understand star schema and the importance for Power BI, 2026, accessed · learn.microsoft.com/en-us/power-bi/guidance/star-schema
Databricks, Work with table history, 2026 · docs.databricks.com/aws/en/tables/history
Discuss the numbers behind your decisions
We can talk about where conflicting reports interrupt decisions and how those figures are used today. A demo can explore the definitions, source data and practical work involved in making the answer easier to trust and maintain.