Alan Chalmers, a British philosopher, explains in his book "What is this thing called science?" that

science is searching for new scientific knowledge and communicating it to the others.

Knowledge, as published through scientific literature, often is the last step in a process originating from research data.These data is analyzed, synthesized, interpreted, and the outcome of this process is usually published as a scientific article. In today’s practice raw scientific data is primarily stored in private files, not in secure institutional repositories, and therefore might get easily lost.

V. Muuli, Estonain Research Council, in his presentation Research Data in Estonia:

Collecting, storing, availibility (2014), points out that 80% of collected research data are stored in researcher's personal computer or institutional server.    

Another survey by Lilian Neerut (UT Library, 2016): Research Data Management and Sharing Practices among the University of Tartu Researchers and Doctoral Students in the Fields of Natural and Exact Sciences and Social Sciences (in Estonian) claims that people are willing to share their data, but in reality the sharing is still rather sporadic or based on internal practices of the research group. Researchers are not sure how to manage and archive their data, guidelines and supporting services are sorely needed. Only few respondents had had any experience in using data repositories. However, the idea of open science was welcomed by many respondents.     

Open Science is the practice of science in such a way that others can collaborate and contribute, where research data, lab notes and other research processes are freely available, under terms that enable reuse, redistribution and reproduction of the research and its underlying data and methods . 

Open Science Taxonomy according to FOSTER.