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Stony Brook University

Data Cleaning and Wrangling Guide

Essential techniques and best practices for preparing ready-to-use data, with implementation examples in Google Sheets, Microsoft Excel, Python, and R.

Welcome!

This guide will support your data work by providing information on essential techniques for having your data ready for analysis. This guide provides practical examples and best practices to ensure your data is accurate and ready for analysis, which include handling missing values, removing duplicates, and transforming data. It also provides information on how to implement these techniques using various tools like Google Sheets, Microsoft Excel, Python, and R, making it suitable for both beginners and experienced users.

Why Data Cleaning and Data Wrangling?

Raw data often arrives in a chaotic and unstructured state, sometimes filled with errors, inconsistencies, and missing values. Attempting to analyze such data without first addressing these issues can result in inaccurate conclusions, wasted time, and ultimately, flawed decision-making.

Data Cleaning
This process is all about identifying and correcting errors, inconsistencies, and inaccuracies within your dataset. Data cleaning may include handling missing values, removing duplicates, and standardizing formats. A proper and thorough data cleaning ensures that your dataset is accurate, consistent, and ready for reliable analysis
 
Data Wrangling
This process is all about transforming and organizing raw data into a more usable and user-friendly format. Data wrangling may include reshaping data, merging multiple datasets, and applying various transformations to make the data analysis process easier. A proper data wrangling is necessary to ensure that your data is structured in a way that maximizes the insights you can gain from it. It also helps streamline the data analysis process, making it more efficient and allowing you to focus on extracting meaningful and valuable information.
 

In a nutshell, data cleaning addresses issues within a dataset, ensuring its accuracy and completeness, while data wrangling reorganizes the data into a format that is easier to work with, enabling more effective analysis and better decision-making. Both of them are vital in getting the data ready for analysis, ensuring that the final insights are based on reliable and well-structured data.