Data Cleaning and Preparation Certification

The Data Cleaning and Preparation Certification is a free 15-minute skill test from Science of Apps. It tests how to clean and prepare data — missing values, duplicates, inconsistent formats, outliers, joining sources, documentation and building repeatable pipelines. Score 70% or more on its 15 questions to earn a verifiable Data Cleaning and Preparation certificate (SOA-DCP). Every question is based on published standards and research — including pandas user guide (pandas), DAMA Data Management Body of Knowledge (DAMA International), e-Handbook of Statistical Methods (NIST) — and each answer is explained with its source.

Read the three skill areas on this page, then take the 15-minute test online — no fee, course or sign-up. You see every answer explained when you finish. Score 70% or more and you get a Data Cleaning and Preparation certificate straight away, on screen, as a PDF and by email, with a credential ID anyone can verify.

Yes. The questions are original scenarios written by Science of Apps, and each one is based on a public source you can read: pandas user guide (pandas); DAMA Data Management Body of Knowledge (DAMA International); e-Handbook of Statistical Methods (NIST); Medallion architecture (Databricks); General Data Protection Regulation (full text) (gdpr-info.eu); Power BI documentation (Microsoft Learn). The source is shown under each question and linked in the answer review. Science of Apps doesn't copy questions from other tests.

Three skill areas with five questions each, drawn from a bank of 10 per area so a retake brings new questions: Cleaning (Missing values, Duplicates and formats and Outliers); Preparation (Joining and reshaping, Validation rules and Repeatable pipelines); Data quality in pipelines (Profiling, Standardisation and enrichment and Privacy in preparation). Every question is an original scenario based on a published standard, official documentation or research, named under the question.

Data analyst, Data engineer, Research analyst, Data scientist and BI analyst. It suits anyone who wants a quick, verifiable way to show Data Cleaning and Preparation skills, from students and career switchers to experienced professionals.

Yes. The test is online, in English and free everywhere — people take it from India, the US, the UK, Europe, Africa, Latin America and Asia-Pacific. Your certificate is dated with your own local date and can be verified from anywhere at scienceofapps.com/certification/verify/.

15 questions — 5 from each of 3 skill areas — with a 15-minute limit. You need 70% (11 of 15) to pass and 90% for distinction.

We rate it Intermediate: assumes hands-on experience in the role. It has 15 scenario questions — 5 from each of 3 skill areas — and a 15-minute limit. You need 70% (11 of 15) to pass and 90% for distinction.

Data cleaning is the hidden test in most data job interviews in 2027: take-homes and live tasks are built with missing values, duplicates, inconsistent formats and outliers to see whether you notice and handle them sensibly. Employers want documented, repeatable cleaning — profiling first, decisions explained, row counts checked and steps saved as code. Practise on messy public data and prove it with a verified test and one well-documented cleaning notebook. Our full career guide covers the hiring process, interview loop, pay and a prep plan: scienceofapps.com/blog/data-cleaning-and-preparation-career-guide/

Nothing. There is no fee to take a test, to receive the certificate, to have it emailed or to verify it, and no sign-up.

On our server, not in your browser. The answers never reach the page until you submit, so a certificate can only be earned by passing. Each certificate gets a unique credential ID stored by Science of Apps.

You see your score for each area and every question with the correct answer and why, with the published source behind it. You can retake after 30 minutes, and the retake draws questions you haven't seen yet.

No. Every certificate is dated, so it always shows when you passed. Retake a test any time for a newer date or a higher score.

Yes. After you pass, Add to LinkedIn opens the Licenses & certifications form with the certificate name, Science of Apps as the issuer, the issue date, your credential ID and the verification link filled in. You can also download it as a PDF or PNG, and it's emailed to you as a PDF.

Every certificate has a credential ID and a QR code. Scanning it, or entering the ID at scienceofapps.com/certification/verify/, shows the holder's name, the certification, the score and the issue date from our records.

No. They are Science of Apps' own assessments of applied skill. They aren't issued by a university or standards body, and they work best alongside a portfolio that shows the skills in real work.