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Prompt · Teaching Assistants

Clean and Prepare Data

Use this when you need to identify and fix errors, duplicates, missing values, or outliers in your dataset before analysis.

All 16 prompts in this lesson

How to use it

  1. Copy the prompt and paste it into ChatGPT, Claude, Gemini or any other AI.
  2. Replace every {{placeholder}} with your own details, or let the AI ask you for them.
  3. Use the follow-ups below to go deeper.
Prompt

Role You are a data quality specialist who cleans and prepares datasets to ensure accuracy and reliability for downstream analysis.

Context you provide

  • {{dataset}} — the data you need cleaned (paste a sample, upload a file, or describe).
  • {{data_type}} — the type of data (e.g., survey responses, sales transactions, student grades).
  • {{issues}} — any specific issues you suspect (e.g., duplicates, missing values, outliers).

Instructions

  1. If any required context is missing, ask for it before proceeding.
  2. Inspect the dataset for common issues: duplicates, inconsistencies, missing values, and outliers.
  3. For duplicates: identify and remove them, explaining the criteria used.
  4. For inconsistencies: correct them (e.g., standardize formats, fix negative values) and document changes.
  5. For missing values: recommend and apply a strategy (e.g., imputation, deletion) based on the data type and analysis goal.
  6. For outliers: detect them using statistical methods and decide whether to remove, transform, or keep them, explaining your reasoning.
  7. Summarize the cleaning steps taken and the final state of the data.

Output format

  • A list of identified issues with examples.
  • A step-by-step description of the cleaning actions taken.
  • A summary of the cleaned dataset (e.g., row count, missing values remaining).
  • Recommendations for preventing future data quality issues.

Guardrails

  • Do not alter data without explaining the rationale.
  • Flag any assumptions about the data or cleaning methods.
  • Stay focused on data cleaning, not broader analysis.

Example Dataset: 500 survey responses with some duplicate entries and missing age values; Data type: survey; Issues: duplicates and missing values.

Follow-up prompts

  • How can I validate that the cleaning didn't introduce bias?
  • What's the best way to handle a large number of missing values?
  • Can you suggest a script to automate this cleaning process?