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Prompt lesson · 13 prompts

Data Cleaning Guidance prompts for Data Analysts

13 ready-to-use prompts from our AI for Data Analysts course. Copy one, fill in the {{placeholders}}, and paste it into ChatGPT, Claude, Gemini or any other AI.

01

Choose Missing Data Imputation Methods

Use this when you need to decide how to handle missing values in a dataset before analysis, with the reasoning behind each method.

Prompt

Role — You are a data analysis advisor who recommends missing-value handling methods matched to a dataset's structure and the analysis it will support.

Context you provide

  • {{dataset_description}} — what the dataset contains, its size, and the variable(s) with missing values
  • {{variable_types}} — whether the affected variables are continuous, categorical, or a mix
  • {{missingness_pattern}} — what you know about the missing data (random, concentrated in certain rows/columns, tied to another variable) — paste a summary if you have one
  • {{downstream_use}} — what the cleaned data will be used for (e.g., a regression model, a report, a dashboard)

Instructions

  1. Ask for any missing context above, especially {{missingness_pattern}} — the right method depends heavily on why data is missing, not just how much.
  2. Recommend 2-3 suitable imputation (or exclusion) methods for {{variable_types}}, explaining the reasoning behind each.
  3. Note the trade-offs of each method: bias risk, effect on variance, and complexity to implement.
  4. Recommend one primary method best suited to {{downstream_use}}, with a fallback if assumptions don't hold.
  5. Flag if the proportion of missing data is high enough that imputation itself becomes risky, and suggest reconsidering the variable's inclusion.

Output format — A short "Missingness assessment" note, a comparison of 2-3 methods (name, how it works, trade-off), and a "Recommended approach" paragraph.

Guardrails — Do not assume a missingness mechanism (random vs. systematic) without evidence from {{missingness_pattern}}; state it as an assumption if inferred. Do not claim a specific tool or library will produce guaranteed results without testing. Flag high missingness (e.g., over 30-40%) as needing a judgment call, not automatic imputation.

Example — dataset_description: "customer churn dataset, 10,000 rows, income field 15% missing"; variable_types: "income is continuous"; missingness_pattern: "more missing among newer customers"; downstream_use: "logistic regression churn model".

Open this prompt Analysis · Intermediate

02

Data Cleaning Documentation Template

Use this when you need to create clear, reproducible documentation for your data cleaning processes.

Prompt

Role You are a data management specialist who helps create thorough, accessible documentation for data cleaning procedures, ensuring transparency and reproducibility.

Context you provide

  • {{dataset}}: The name or description of the dataset you cleaned.
  • {{cleaning_steps}}: The specific steps you took (e.g., removing duplicates, handling missing values, standardizing formats).
  • {{tools_used}}: Any software or scripts used (e.g., Python, Excel, SQL).
  • {{team_collaboration}}: Whether the documentation will be shared with a team and any collaboration needs.

Instructions

  1. Ask for any missing context before starting.
  2. Create a comprehensive documentation template that includes sections for dataset description, cleaning steps, tools used, and version control.
  3. Include a checklist for documenting cleaning procedures, emphasizing version control and reproducibility.
  4. Provide best practices for keeping the documentation up-to-date and accessible for team collaboration.
  5. Suggest how to handle challenges like incomplete records or ambiguous cleaning decisions.

Output format Present the template as a structured Markdown document with clear headings, bullet points, and placeholders for user-specific details. Include a checklist at the end. Keep the tone professional and instructional.

Guardrails

  • Do not assume specific cleaning steps; use only what the user provides.
  • Flag any missing information that could affect documentation completeness.
  • Stay focused on documentation; do not provide general data cleaning advice unless asked.

Example

  • {{dataset}}: Customer sales data from Q1 2024, {{cleaning_steps}}: removed duplicate transactions, imputed missing zip codes, standardized date formats, {{tools_used}}: Python pandas, {{team_collaboration}}: shared with data team via Confluence.

Open this prompt Creating · Beginner

03

Data Duplication Management

Use this when you need to identify, remove, and prevent duplicate records in your dataset to ensure data accuracy.

Prompt

Role You are a data quality specialist who helps me detect and eliminate duplicate records, and implement strategies to prevent future duplication.

Context you provide

  • {{dataset}}: The name or description of the dataset.
  • {{duplicate_criteria}}: What defines a duplicate (e.g., same email, same combination of fields).
  • {{current_issues}}: Any known challenges or symptoms of duplication (e.g., inflated counts, inconsistent records).
  • {{tools}}: The tools or platforms you use (e.g., Excel, Python, SQL).

Instructions

  1. Ask for any missing context before starting.
  2. Identify strategies to detect duplicates based on the given criteria, such as exact matching or fuzzy matching.
  3. Provide step-by-step methods to remove duplicates while preserving data integrity.
  4. Discuss common challenges in deduplication (e.g., false positives, large datasets) and how to overcome them.
  5. Suggest best practices and automated processes to prevent future duplication.

Output format Structure the response with sections: Detection Strategies, Removal Methods, Challenges & Solutions, and Prevention Best Practices. Use bullet points and practical examples. Keep the tone actionable and clear.

Guardrails

  • Do not assume the dataset's structure; base recommendations on the provided criteria and tools.
  • Flag any assumptions about data quality or missing fields.
  • Stay focused on duplication; do not cover other data quality issues unless relevant.

Example

  • {{dataset}}: CRM contacts, {{duplicate_criteria}}: same email address, {{current_issues}}: multiple records for same customer, {{tools}}: Python pandas and SQL.

Open this prompt Analysis · Intermediate

04

Data Integrity Issue Resolution

Use this when you need to identify and resolve data integrity issues to maintain the reliability of your dataset.

Prompt

Role You are a data governance expert who helps me identify, resolve, and prevent data integrity issues to ensure my analyses are trustworthy.

Context you provide

  • {{dataset}}: The name or description of the dataset.
  • {{integrity_concerns}}: Any specific issues you suspect (e.g., missing values, inconsistent formats, outliers).
  • {{industry}}: The industry context (e.g., finance, healthcare) that may have specific integrity requirements.
  • {{tools}}: The tools or systems you use (e.g., SQL, Python, data warehouses).

Instructions

  1. Ask for any missing context before starting.
  2. Identify potential data integrity issues based on the dataset description and concerns.
  3. Provide a systematic approach to resolve these issues, including validation rules and cleaning techniques.
  4. Explain the role of data validation in maintaining integrity and how to implement it effectively.
  5. Suggest metrics to evaluate data integrity and governance practices to enhance it.

Output format Structure the response with sections: Potential Issues, Resolution Steps, Validation Role, and Integrity Metrics. Use bullet points and practical examples. Keep the tone professional and solution-oriented.

Guardrails

  • Do not assume specific issues; base analysis on the provided concerns and dataset.
  • Flag any assumptions about data quality or missing information.
  • Stay focused on data integrity; do not deviate into unrelated data topics.

Example

  • {{dataset}}: Financial transactions, {{integrity_concerns}}: missing timestamps and inconsistent currency codes, {{industry}}: finance, {{tools}}: SQL and Python.

Open this prompt Analysis · Intermediate

05

Data Normalization Guide

Use this when you need to normalize numerical variables in a dataset to ensure comparability and improve analysis accuracy.

Prompt

Role You are a data preprocessing expert who guides me through normalizing numerical variables to make my dataset suitable for analysis and modeling.

Context you provide

  • {{dataset}}: The name or description of the dataset.
  • {{variables}}: The numerical variables that may need normalization.
  • {{analysis_goal}}: The intended use of the data (e.g., regression, clustering, machine learning).
  • {{data_scale}}: Whether the variables have different units or scales (e.g., age vs. income).

Instructions

  1. Ask for any missing context before starting.
  2. Explain the concept of data normalization and why it is important for comparability.
  3. Identify which variables in the dataset likely need normalization based on their scale and distribution.
  4. Provide a step-by-step guide for normalizing the specified variables, including methods like min-max scaling, z-score standardization, and robust scaling.
  5. Discuss potential issues with non-normalized data and how normalization impacts analysis results.

Output format Structure the response with sections: Why Normalize, Variables to Normalize, Step-by-Step Guide, and Impact on Analysis. Use bullet points and code snippets where helpful. Keep the tone educational and practical.

Guardrails

  • Do not assume the dataset's content; base recommendations on the provided variables and goal.
  • Flag any assumptions about data distribution or missing values.
  • Stay focused on normalization; do not cover other preprocessing steps unless relevant.

Example

  • {{dataset}}: Customer demographics, {{variables}}: age, income, spending score, {{analysis_goal}}: k-means clustering, {{data_scale}}: age in years, income in USD, spending score 1-100.

Open this prompt Analysis · Intermediate

06

Detect And Handle Data Outliers

Use this when you need a clear plan for identifying outliers in a dataset and deciding how to treat them.

Prompt

Role — You are a data analyst who explains outlier detection methods clearly and helps decide how to treat outliers responsibly.

Context you provide

  • {{dataset_description}} — what the dataset contains, its size, and the field or fields you suspect have outliers
  • {{analysis_goal}} — what the data will be used for, such as forecasting or reporting
  • {{tooling}} — what software or language you're using, if any

Instructions

  1. Ask for the dataset description and analysis goal if missing.
  2. Recommend 2-3 outlier detection methods appropriate to {{dataset_description}}, such as z-score, IQR, or visual inspection, explaining when each fits best.
  3. Explain how to apply the recommended method using {{tooling}}, in general terms or with sample formulas or code.
  4. Discuss treatment options, such as removal, capping, transformation, or flagging for separate analysis, and how to choose based on {{analysis_goal}}.
  5. Warn about the risk of removing legitimate extreme values that matter for {{analysis_goal}}.

Output format — A short explainer with sections: Detection Method, How To Apply It, Treatment Options. Under 350 words.

Guardrails

  • Do not claim to have analyzed the actual data; this is guidance, not a completed analysis.
  • Always note that outlier treatment should be reversible and documented, not silently deleted.
  • Flag when a value that looks like an outlier might actually be a meaningful signal.

Example — {{dataset_description}} = 10,000-row sales dataset, suspected outliers in transaction amount; {{analysis_goal}} = monthly revenue forecasting; {{tooling}} = Python with pandas.

Open this prompt Analysis · Intermediate

07

Identify and Resolve Data Quality Issues

Use this when you need to systematically identify and address data quality issues in a dataset to ensure reliable analysis.

Prompt

Role You are a senior data quality analyst. Your goal is to help me systematically identify, resolve, and prevent data quality issues in my dataset to ensure reliable analysis.

Context you provide

  • {{dataset}}: The name or description of the dataset to analyze.
  • {{specific_concerns}}: Any known issues or areas of concern (optional).

Instructions

  1. If I haven't provided the dataset or specific concerns, ask me for them before starting.
  2. Outline a step-by-step approach to identify data quality issues, including techniques like profiling, validation, and outlier detection.
  3. Provide specific methods to address each type of issue (e.g., missing values, duplicates, inconsistencies).
  4. Recommend tools or frameworks that can assist in the process.
  5. Suggest metrics to measure data quality and how to monitor it over time.

Output format Provide a structured response with sections: 'Identification Steps', 'Resolution Methods', 'Tools & Frameworks', 'Metrics & Monitoring'. Use bullet points and keep it concise but detailed.

Guardrails

  • Do not invent specific data issues; base recommendations on general best practices.
  • Flag any assumptions about the dataset or context.
  • Stay focused on data quality; do not drift into unrelated analysis.

Example Dataset: 'customer_transactions.csv', specific concerns: 'missing values in age column and duplicate records'.

Open this prompt Analysis · Intermediate

08

Plan A Data Deduplication Process

Use this when duplicate records are undermining a dataset and you need a plan to find and remove them.

Prompt

Role — You are a data quality analyst who designs practical deduplication processes that protect data integrity without deleting records that only look similar.

Context you provide

  • {{dataset_description}} — what the dataset contains and roughly how large it is
  • {{duplicate_pattern}} — what a duplicate looks like in this dataset, such as matching emails or names with typos
  • {{tools_available}} — spreadsheet, database, or dedicated tool you can use
  • {{risk_tolerance}} — how cautious you need to be about false-positive matches

Instructions

  1. Ask for {{dataset_description}} and {{duplicate_pattern}} if not provided.
  2. Recommend a matching approach — exact match, fuzzy match, or rule-based — suited to {{duplicate_pattern}} and {{tools_available}}.
  3. Lay out the steps to identify candidate duplicates, review them, and merge or remove them safely.
  4. Suggest a way to verify accuracy before deleting anything, given {{risk_tolerance}}.
  5. Recommend one safeguard to prevent new duplicates from being created going forward.

Output format — A short recommended-approach paragraph, then a numbered step-by-step process, ending with a one-line prevention tip. Under 320 words.

Guardrails — Do not recommend permanently deleting records without a review or backup step. Do not claim a specific tool or algorithm works without the user confirming it fits {{tools_available}}. Flag when {{duplicate_pattern}} is too vague to design a reliable rule.

Example — dataset_description: a 50,000-row customer contact list; duplicate_pattern: same email with different name spellings; tools_available: spreadsheet and SQL; risk_tolerance: low, prefer manual review before deleting.

Open this prompt Planning · Intermediate

09

Standardize Data Across Sources

Use this when you need to ensure consistency when working with data from multiple sources or formats.

Prompt

Role You are a data management expert specializing in data standardization. Your goal is to help me achieve consistency across datasets from multiple sources.

Context you provide

  • {{dataset}}: The dataset(s) or data sources to standardize.
  • {{formats}}: The different formats or structures currently in use (optional).

Instructions

  1. If I haven't provided the dataset or formats, ask for them before starting.
  2. Outline a step-by-step process for standardizing data, including mapping fields, normalizing formats, and handling discrepancies.
  3. Discuss common challenges in data standardization and how to address them.
  4. Compare manual vs. automated standardization approaches, including pros and cons.
  5. Provide examples of industries where standardization is critical and lessons learned.

Output format Present a clear guide with sections: 'Standardization Steps', 'Challenges & Solutions', 'Manual vs. Automated', 'Industry Examples'. Use bullet points and practical advice.

Guardrails

  • Do not assume specific data formats; ask if unclear.
  • Avoid recommending specific tools without noting they are examples.
  • Stay focused on standardization; do not expand into broader data governance unless relevant.

Example Dataset: 'sales_data_2024.xlsx' and 'customer_data.csv', formats: 'dates in different formats, inconsistent country codes'.

Open this prompt Analysis · Intermediate

10

Standardize Inconsistent Data Formats

Use this when you need to standardize mixed date or category formats in a real dataset sample.

Prompt

Role — You are a data quality analyst who standardizes inconsistent formats in a dataset you're shown.

Context you provide

  • {{dataset_description}} — what the dataset is and its relevant columns
  • {{data_sample}} — a representative sample showing the format inconsistencies
  • {{target_format}} — optional: the standard format to convert to, e.g., ISO date format

Instructions

  1. Ask for any missing inputs, especially {{data_sample}} — recommendations must be based on the actual inconsistencies shown.
  2. Identify the format inconsistencies present in {{data_sample}}: mixed date formats, inconsistent capitalization or spelling of categorical values, mixed units.
  3. Propose a standardization rule for each type found, converting to {{target_format}} where specified or a sensible default otherwise, with before/after examples.
  4. Flag any conversions that are ambiguous, such as a date that could be read as MM/DD or DD/MM, and need human confirmation rather than an automatic fix.
  5. Recommend a validation step to prevent these inconsistencies going forward.

Output format — A table of Inconsistency Type, Example (Before), Standardized (After), Fix Rule, followed by Ambiguous Cases and a Prevention Recommendation. Practical, data-cleaning tone.

Guardrails — Never invent inconsistencies not visible in {{data_sample}}; flag ambiguous conversions instead of guessing; never silently change data that could alter meaning without flagging it.

Example — dataset_description: "transaction log with a 'date' and 'category' column"; data_sample: "[pasted 15 rows showing '03/04/2025', '2025-04-03', and 'Apr 3 25' in the date column]".

Open this prompt Analysis · Intermediate

11

Standardize Inconsistent Data Values

Use this when you need to diagnose and fix inconsistent values in a real dataset sample.

Prompt

Role — You are a data quality analyst who diagnoses and proposes fixes for inconsistent values in a dataset you're shown.

Context you provide

  • {{dataset_description}} — what the dataset is and its columns
  • {{data_sample}} — a representative sample showing the inconsistencies
  • {{field_of_concern}} — optional: the specific column or variable with the worst issues

Instructions

  1. Ask for any missing inputs, especially {{data_sample}} — recommendations must be based on the actual inconsistencies shown, not generic advice.
  2. Identify the types of inconsistency present in {{data_sample}}: typos, inconsistent casing/formatting, synonyms, mixed units, duplicate categories.
  3. Propose a standardization rule for each inconsistency type found, with a before/after example from the data.
  4. Recommend a validation step to catch these issues going forward, such as a dropdown list, a regex check, or a reconciliation step.
  5. Note any values that are ambiguous and need a human decision rather than an automated fix.

Output format — A table of Inconsistency Type, Example (Before), Standardized (After), Fix Rule, followed by a Prevention Recommendations list. Practical, data-cleaning tone.

Guardrails — Never invent inconsistencies not visible in {{data_sample}}; flag ambiguous cases instead of guessing the "correct" value; keep fixes proportional to the data's actual scale.

Example — dataset_description: "customer records, 'country' and 'state' fields"; data_sample: "[pasted 20 rows showing 'USA', 'U.S.A', 'United States', and blank values in the country column]".

Open this prompt Analysis · Intermediate

12

Standardize Inconsistent Units In A Dataset

Use this when you have a dataset that mixes measurement units and need a reliable plan to standardize it before analysis.

Prompt

Role — You are a data cleaning advisor who helps standardize inconsistent units of measurement across a dataset.

Context you provide

  • {{dataset_description}} — what the data contains and how it's structured
  • {{unit_inconsistencies}} — which units are mixed (e.g., miles vs. km, lbs vs. kg)
  • {{target_unit}} — the unit to standardize everything to

Instructions

  1. Ask for the dataset description and target unit if not provided.
  2. Identify where inconsistent units most likely appear based on the description.
  3. Give the correct conversion formula or factor for each unit pair involved.
  4. Suggest a standardization method (a conversion column, formula, or script) and how to flag entries with an ambiguous or missing unit.
  5. Recommend a validation check to confirm the conversions are correct.

Output format — A conversion reference table (From Unit | To Unit | Formula/Factor), a short step-by-step standardization plan, and a validation checklist.

Guardrails

  • Use only standard, verifiable conversion factors.
  • Flag any entry where the original unit is ambiguous rather than guessing.
  • Recommend spot-checking a sample of converted values against source records.

Example — {{dataset_description}} = shipment weight records from multiple vendors; {{unit_inconsistencies}} = a mix of lbs and kg with no unit column; {{target_unit}} = kilograms.

Open this prompt Analysis · Intermediate

13

Validate Data Against Predefined Rules

Use this when you need to validate a dataset against predefined rules to identify errors and ensure reliability.

Prompt

Role You are a data quality assurance specialist. Your goal is to help me validate my dataset against predefined rules, identify errors, and suggest resolutions.

Context you provide

  • {{dataset}}: The dataset to validate.
  • {{rules}}: The predefined rules or validation criteria (if any).

Instructions

  1. If I haven't provided the dataset or rules, ask for them before starting.
  2. Outline a step-by-step approach to validate the dataset against the rules.
  3. Identify common types of validation errors (e.g., format, range, consistency) and how to detect them.
  4. Suggest strategies for resolving errors, including automated checks.
  5. Recommend metrics to evaluate the success of validation efforts.

Output format Provide a structured response with sections: 'Validation Approach', 'Common Errors', 'Resolution Strategies', 'Metrics'. Use bullet points and clear examples.

Guardrails

  • Do not claim to have validated the actual data unless provided; focus on methodology.
  • Flag any assumptions about the rules or data.
  • Stay within the scope of validation; do not delve into broader data analysis.

Example Dataset: 'employee_records.csv', rules: 'age between 18 and 65, email format valid'.

Open this prompt Analysis · Intermediate