Data analyst portfolio: a project review checklist
A data analyst portfolio should show how you moved from a question to a defensible decision. A dashboard screenshot can show presentation skill, but a reviewer also needs the definition, query, checks and limits behind it.
Choose a question with a decision
For a suggested project, ask which customer segment needs further investigation after a decline in completed orders. Define the population, completion event, date range and comparison. Explain what action the result could inform and what the dataset cannot establish.
Document and check the source
Use permitted public or synthetic data. Include a data dictionary, keys, missing-value treatment and source date. Check whether joins increase row counts unexpectedly and whether totals reconcile. Record exclusions such as test transactions so another person can understand the population.
Make the analysis reproducible
Save the SQL or spreadsheet steps and provide setup instructions. Use relative paths and remove secrets. A reviewer should be able to rerun the analysis from the supplied data and see how the final values were produced. Explain any manual step instead of hiding it.
Choose a chart that answers the question
Label units, dates and denominators. Separate an overall trend from differences between segments. Provide a short explanation and relevant limitation beside the chart. Do not claim causality from a before-and-after picture without a suitable study design.
Show how you review assisted work
If an approved AI tool helped draft SQL or text, explain how you checked its output. Test a query against known cases and inspect joins, filters and definitions. Do not upload private data to an unapproved service or claim independent work you cannot explain.
Package the evidence for hiring
Open with the question, method, result and limitation. Link the query, reproducible files and a readable visual. Keep measured outcomes only when the project actually observed them. A hypothetical recommendation should not become a fabricated revenue improvement in your CV.
Sources and next steps
Sources checked on October 2, 2026. Follow the linked documentation for current requirements.