At least some of the following characteristics apply:
- There are huge amounts of data
- The data changes very often
- It is difficult to structure the data so that it can be used easily
Big data is used to analyse different subjects. Through the analysis, new information can be gained. Bigger amounts of data make it easier to find reliable information. It is used in many different areas, such as government, health care, insurance, media, advertisement and information technology.
The data is gathered among other things through:
- the use of credit cards
- Electronic Communication (for example E-mail and smartphones)
- Internet and social media (for example from using Google search or when visiting Facebook)
- Internet of things (objects that can connect to the internet, for example Amazon Alexa)
- governments and public authorities (for example tax data, census data)
Big data has been criticised for different reasons. One prominent criticism is the increasing surveillance to gather data, which takes place in many new forms. Edward Snowden has revealed how the American National Security Agency (NSA) uses digital technology to spy on people around the world. Another prominent criticisms is data privacy, which is about the risk of sensitive personal data leaking because it is not protected well enough.
A more fundamental critique of big data is just because it is bigger, it is not automatically better. The quality of the data still has to be controlled. It also says that data analysis can only ask "what" is happening, but not "why" it is happening.