Data cleaning is the process of fixing or removing incorrect, corrupted, incorrectly formatted, duplicate, or incomplete data within a dataset. It is a crucial step in data mining, as the insights and analysis are only as good as the data being used. Data cleaning is also referred to as data cleansing, data scrubbing, or data wrangling. The process of data cleaning varies from dataset to dataset, and there is no one absolute way to prescribe the exact steps. However, some common steps in the data cleaning process include:
-
Identifying errors: This involves identifying incorrect, incomplete, duplicate, or otherwise erroneous data in a dataset.
-
Removing irrelevant data: Some data may not be relevant to analytics applications and could skew their results. Data cleansing removes redundant data from data sets, which streamlines data preparation and reduces the required amount of data processing and storage resources.
-
Filling in missing values: Missing values can be filled with appropriate values using various approaches such as filling the values manually, using the same global constant, or using the attribute mean.
-
Smoothing noisy data: Noise is a random error or variance in a measured variable. Smoothing methods such as binning can be used to handle noise.
-
Ensuring consistency and uniformity: Data should be consistent within the same dataset and/or across multiple data sets.
Data cleaning is a time-consuming and tedious process, but it is essential to guarantee the accuracy, integrity, and security of business data. It improves data quality and helps provide more accurate, consistent, and reliable information for decision-making in an organization.