Data Cleaning is the method of identifying the incomplete, wrong, unnecessary, incorrect, or missing part of the data and then changing, replacing, or removing them according to the specific requirement.
Table of Contents:
Difficulties that occur with the Data
Best Practises for Data Cleaning
Data is the most important thing for Machine learning and Analytics. In Business or computing data is needed everywhere. When we are talking about real-world data, the data may contain incomplete, irregular, or missing values. If the data is corrupted then it may delay or stop the process or provide inaccurate results. Let’s discuss the importance of data cleaning.
Data cleaning is the process of standardizing data to make it suitable and ready for analysis. Sometimes there are inconsistencies in the data like inaccurate data formats, missing data, errors while capturing the data. So, data cleaning is an important step in data science projects. The accuracy of the results depends on the data we use.
Data cleaning is a critically crucial step in any machine learning project. There are several different statistical analysis and data visualization techniques that you can use to explore your data to identify data cleaning action that you may need to perform.
There are a few basic data cleaning techniques in machine learning like identifying and deleting columns with a single data value, identifying, and removing rows that contain duplicate values, etc, you can easily perform these operations on all your single machine learning project. These are so important that if skipped, models may break or report excessively optimistic performance results.
The main purpose of Data Cleaning is to find and remove errors along with any duplicate data, to build a reliable dataset. This increases the quality of the training data for analytics and facilitates decision-making.
Difficulties that Occur with the Data:
There are many problems that are encountered while working with data:
Models that are equipped with insufficient data generally result in poor predictions which in turn leads to either overfitting or underfitting.
Too Much Data
Excessive data can either be outdated historical data i.e. too many rows or, have too many columns. This can be reduced by dimensionality reduction techniques.
Gathered data has errors that can have a significant impact on the ML model. when the data is not biased, solved by oversampling and undersampling.
This can be solved by data deletion or data imputation.
Understand from known data i.e., fill in missing values with column mean, include from other nearby values, create an ML model to predict missing value; sort records and use previous data for the missing value.
Records in a dataset can be identified as outliner by calculating the distance from the mean line. Once recognized, these records can either be dropped or set to mean.
Best Practises for Data Cleaning
Mentioned below are some of the best data cleaning techniques for machine learning:
Conclude A Plan
When we talk about data cleaning, the first step is to conduct data profiling which helps in separating data and identifying spot problems or outlier values or in data. Now once the profiling process is finished, it normalizes the field, de-duplicates it, eliminates obsolete information, and more. You should have your goals and expectation planned that will help in making an excellent overall plan and strategy to carry out data cleaning.
Uniform Data Standards Is the Way
For effective data cleaning, you should have a uniformed data standard to produce better and efficient results. It helps improves the initial data quality, thereby reducing the steps further. It generates a decent quality of data which is easier to clean rather than the data which is low quality. Making corrections at the data entry point is the most important step in ensuring overall data cleaning. To assure data standards, several companies believe in building data entry standards documents that help in the long run.
Validating the Accuracy of Data
The data that is collected should always be genuine and authentic to avoid re-runs and errors in programs. It should be able to meet the required standards, and the source should be accurate. Validating the accuracy of data is an important step, and can improve the overall quality of data sets, the process can be challenging and complex. One of the effective ways is to validate small data at a time or create a script, particularly when dealing with large datasets. It also helps in eliminating duplications, identifying out-of-date records and other additional errors in the dataset.
Identifying & Adding the Missing Data
The next step that comes into the role after you have validated the data is the step of adding the missing data. Cross-referencing different data sources and combining known data into the final data set that is considerably more useful and relevant. This step is necessary to provide complete information for business analytics and intelligence. After checking the usability of the dataset, the whole data cleaning process can be automated to avoid human error, which helps saving significant time and money.
Monitoring the System
Setting up automation is an important step, but monitoring the entire data cleansing process is an extremely essential process. It checks the overall health along with the effectiveness of the system. It also checks if the data is as per the standards and that all procedures have been followed accurately. Implementing periodic checks help in keeping the situation under control.
Data Cleaning is considered as a very important aspect if you want to make your analytics and machine learning models error-free and result-oriented. A small or minor error in the dataset can cause you a lot of problems. All your efforts and the time that you invested can be wasted. So, always try to make your data clean and error-free.