Why a report needs its own check
A weekly or monthly report is usually put together from exports: income and costs from the accounting system, cash from the bank, open invoices from the receivables list. Each step can go wrong without an error: a filter left on, a month cut short, a row counted twice. The report still looks finished. The simplest protection is to compare its main figures with the figures the source system reports itself, every time, before anyone reads it.
Pick the figures that must agree
You do not need to check every line. Pick the few figures the reader will act on and write them down as a short list. Keep each currency as its own figure: a total in euros and one in Czech crowns are two figures to check, never one sum.
- Total income and total costs for the period, as two separate figures.
- Cash at the end of the period, per account.
- Open receivables: what customers still owe.
- Any comparison figure, such as last month or the same month last year.
Get the system's own report
Most accounting and invoicing systems can export their own summary reports, such as a profit and loss or an aged receivables list, as a CSV or spreadsheet file. Export that report for the same period, separately from the exports the report was built from. Save it next to the finished report, so anyone can see later what it was checked against.
Compare, and stop on any difference
Put each figure from your report next to the same figure from the system's report and mark it. Decide in advance whether any difference is allowed for rounding; the safest default is none.
- Agrees: the same amount. 100 and 100.00 are the same amount, so compare values, not text.
- Differs: show both figures and the difference.
- Missing: the figure is not in the system's report. A missing figure stops the report; it never passes.
- Unreadable: a cell such as n/a. Stop and ask; never read it as zero.
Fix the cause, not the figure
When a figure differs, the finished report is not where the fix belongs. If one client's report stops, the others can still go ahead. Look for the cause in the export or in the steps that built the report: a wrong period, a missing file, a filter. Fix it there, build the report again and check again. Changing the figure by hand only hides the problem until next month. When the check passes, a person still reads the report and approves it before it goes out.
When it is worth building something
Once several reports go out each month, a short script can run the comparison for every client, list each figure it checked, hold back any report that does not agree and write a note saying which figure to look at. A person fixes what it finds and approves each report. The desk's workflows include this check, shown on made-up data.