The unit of analysis refers to the main parameter that you’re investigating in your research project or study. Example of the different types of unit analysis that may be used in a project include:
- Individual people
- Groups of people
- Objects such as photographs, newspapers and books
- Geographical unit based on parameters such as cities or counties
- Social parameters such as births, deaths, divorces
The unit of analysis is named as such because the unit type is determined based on the actual data analysis that you perform in your project or study.
For example, if your research is based around data on exam grades for students at two different universities, then the unit of analysis is the data for the individual student due to each student having an exam score associated with them.
Conversely if your study is based on comparing noise level data between two different lecture halls full of students, then your unit of analysis here is the collective group of students in each hall rather than any data associated with an individual student.
In the same research study involving the same students, you may perform different types of analysis and this will be reflected by having different units of analysis. In the example of student exam scores, if you’re comparing individual exam grades then the unit of analysis is the individual student.
On the other hand, if you’re comparing the average exam grade between two universities, then the unit of analysis is now the group of students as you’re comparing the average of the group rather than individual exam grades.
These different levels of hierarchies of units of analysis can become complex with multiple levels. In fact, its complexity has led to a new field of statistical analysis that’s commonly known as hierarchical modelling.
As a researcher, you need to be clear on what your specific research question is. Based on this, you can define each data, observation or other variable and how they make up your dataset.
A clarity of your research question will help you identify your analysis units and the appropriate sample size needed to obtain a meaningful result (and is this a random sample/sampling unit or something else).
In developing your research method, you need to consider whether you’ll need any repeated observation of each measurement. You also need to consider whether you’re working with qualitative data/qualitative research or if this is quantitative content analysis.
The unit of analysis of your study is the specifically ‘who’ or what’ it is that your analysing – for example are you analysing the individual student, the group of students or even the whole university. You may have to consider a different unit of analysis based on the concept you’re considering, even if working with the same observation data set.