How to compare a machine-generated report with a correction

You have a report created by software or AI, plus a corrected copy. You need to know exactly what changed, and whether the correction removed or altered anything important.

For Word documents, its Compare feature can show insertions and deletions in a separate review copy. If your reports are CSV files, you can inspect their contents in TooLab's CSV Editor, but it does not create a difference report. The steps below help you choose the right approach and check the changes carefully.

Compare the original and corrected report

1. Keep the originals unchanged. Make separate copies and label them clearly, such as original and corrected. If the files are CSV, open them in the CSV Editor to inspect the columns and search for values. It can help you review each file, but it does not compare two versions automatically.
2. Open the documents in Word. For Word files, open the desktop version of Microsoft Word. On Windows, choose Review › Compare › Compare. On macOS, choose Review › Compare › Compare Documents. Menu wording can differ slightly between versions.
3. Select the two versions. Choose the machine-generated report as the original and the corrected copy as the revised document. Add labels that make the sources clear, such as Generated report and Corrected report.
4. Choose what to compare. Leave insertions and deletions enabled. If the documents have lots of layout changes, turn off formatting comparisons to make the text changes easier to review. Then run the comparison.
5. Review and save the result. Word creates a new document showing the differences. Read each change in context, then save the comparison under a new name. Keep both source files as they were.

If your report is plain text, open a copy in Word and save it as a Word document before comparing. For a PDF, use a text export or copy the text into separate documents, then check any tables and line breaks by eye. Converting a PDF can change layout, so do not treat formatting differences as proof that the report's contents changed.

What the comparison means

Text appears as an insertion or deletion

Word marks text present in one version but not the other. An insertion in the corrected copy may be an added explanation or a restored sentence. A deletion may be an intentional cleanup, but it could also remove a qualification, warning, or result. Read the words before and after the change, not just the highlighted fragment.

A number, date, or unit changed

Treat this as a factual change, even if it is only one character. Check values such as 0.8 versus 8, percentages, dates, currency, and measurement units against the source data or a reliable record. A text comparison can show that a value changed, but it cannot tell you which value is correct.

A large passage is marked as changed

The report may have been reorganized, or formatting and line breaks may have changed. Compare the meaning and the sequence of facts. If the same information has moved to a different section, confirm it is still attached to the right heading, table row, or conclusion.

Almost nothing is marked

The documents may be identical, or the correction may have changed formatting that you excluded. Check that you selected the intended files and that the corrected copy was saved after editing. If a person corrected a scanned image or a flattened PDF, the text may not be available for a reliable comparison until it is converted.

How to fix a confusing comparison

1. Remove formatting noise. Run the comparison again with formatting changes turned off. This helps when font, spacing, or page layout changed but the words did not.
2. Check that the right files were selected. Open each source separately and verify its title, date, or first sentence. A comparison of two copies of the same version will not reveal the correction.
3. Compare like with like. If one report has been restructured, compare sections or tables with the same headings and row identifiers. For CSV files, use a stable ID such as a record number to locate the same item in each version. Comparing row positions alone can be misleading if rows were added or sorted.
4. Restore readable text from the source. If a PDF or scan produces scrambled words, use the original editable document if you can. Optical character recognition, which converts a picture of text into editable text, can misread numbers and punctuation.
5. Ask for the correction source when a change is unexplained. If a key figure or conclusion differs and you cannot verify it, check the underlying data or ask the person who made the correction. Do not accept a value simply because it appears in the newer file.

What a comparison cannot verify

A comparison identifies differences between two files. It does not prove that the corrected version is accurate, that every generated error was found, or that the report was based on valid data. A correction can leave an incorrect sentence unchanged, or replace a wrong number with another wrong number.

For a high-stakes report, check every changed result against its source and review unchanged claims that matter to the decision. If the report contains personal or confidential information, use an approved local application and follow your organization's rules before opening it in an online tool.