There are two forms of data which is used bi sociologists in evaluating educational or any other systems: qualitative and quantitative. 
Quantitative data is a data in the forms of numbers. It is widely used by researches because it enables them to give the whole picture of the situation in any section and prove their point of view by using some statistics or facts. Another way of using the quantitative data is comparing and measuring relations between different factors affecting education. If, for example we are given ages and time spent on doing homework of the group of people we can conclude which age group spend most of their time on doing homework and which the least. There are many examples of quantitative data.
Another type of data is qualitative which refers to all other types of data excluding numbers. It gives richer and clearer image of the situation. Qualitative data has different types. It includes: data from direct observations, interviews, photos and videos, written documents. By examining this data’s resources we will provide not only the whole picture of social life, but also will give variable sources of information.


There are two methods of making a research: positivism and interpretivism. Both these methods are suitable for evaluating educational system and explaining some inconsistencies.
Interpretivists believe that to understand and explain behavior of people and to have clearer picture of them it is necessary to study the way they think, their ideas. For these researches the most factual and significant type of data is qualitative. Participant observation, that is observation which involves researchers in participating in activities of those who are being observed. Interviews are also very useful kind of data as it gives an opportunity to talk to people about their norms, behavior as they see it. 
While positivists believe that the most significant data is quantitative. Use of statistics, comparisons explaining the behavior of people who were being observed, easier as we make a comparisons and state facts about the past to prove our point of view. Questionnaires are very useful way of interpreting data and explain human behavior.


The official statistics are the data which is produced by national and local governments. Official statistics provide a wide range of quantitative data, however researchers before using these statistics should know how the statistics are constructed, which surveys they are based on. And if statistics don’t say about their sources of data, researchers might make wrong conclusion of their research. Another limitation of official statistics is that as they are constructed by government, so the government must provide data according to its political purpose and priorities. However there are many advantages of Official Statistics, such as they are well planned and organized and usually take into account different types of data; also they are up to dated and so it gives to researchers opportunities to make comparisons: for example, comparing exam results in the school this year and last year.