the data science process start with data stored within the company your first act should be to assess the relevance and quality of the data that' readily available within your company most companies have program for maintaining key dataso much of the cleaning work may already be done this data can be stored in official data repositories such as databasesdata martsdata warehousesand data lakes maintained by team of it professionals the primary goal of database is data storagewhile data warehouse is designed for reading and analyzing that data data mart is subset of the data warehouse and geared toward serving specific business unit while data warehouses and data marts are home to preprocessed datadata lakes contains data in its natural or raw format but the possibility exists that your data still resides in excel files on the desktop of domain expert finding data even within your own company can sometimes be challenge as companies growtheir data becomes scattered around many places knowledge of the data may be dispersed as people change positions and leave the company documentation and metadata aren' always the top priority of delivery managerso it' possible you'll need to develop some sherlock holmes-like skills to find all the lost bits getting access to data is another difficult task organizations understand the value and sensitivity of data and often have policies in place so everyone has access to what they need and nothing more these policies translate into physical and digital barriers called chinese walls these "wallsare mandatory and well-regulated for customer data in most countries this is for good reasonstooimagine everybody in credit card company having access to your spending habits getting access to the data may take time and involve company politics don' be afraid to shop around if data isn' available inside your organizationlook outside your organization' walls many companies specialize in collecting valuable information for instancenielsen and gfk are well known for this in the retail industry other companies provide data so that youin turncan enrich their services and ecosystem such is the case with twitterlinkedinand facebook although data is considered an asset more valuable than oil by certain companiesmore and more governments and organizations share their data for free with the world this data can be of excellent qualityit depends on the institution that creates and manages it the information they share covers broad range of topics such as the number of accidents or amount of drug abuse in certain region and its demographics this data is helpful when you want to enrich proprietary data but also convenient when training your data science skills at home table shows only small selection from the growing number of open-data providers