Qualitative vs quantitative

Learn the difference between the two main types of data

Data can be broadly categorised as quantitative (numbers) and qualitative (descriptions). Quantitative data measures things, while qualitative data describes things. For example, you could categorise rocks at the bottom of a cliff as small, medium or large – this would be qualitative – but measuring the size of the rocks or counting the number in each category would be quantitative.

Quantitative data lends itself to statistical analysis, whereas qualitative data is harder to analyse in this way. Quantitative data can be used to make generalisations such as ‘prolonged exposure to sunlight increases the likelihood of skin cancer,’ while qualitative data can illustrate particular examples of something, but can be harder to generalise.

Think about the following pieces of data and whether they are qualitative or quantitative:

  • height
  • favourite colour
  • what happened during your trip to school
  • what time you got up this morning
  • how many siblings you have
  • concentration of fluoride ions in tap water.

Note that you can create quantitative data from qualitative data: for example, by collecting descriptions from different people about how they get to school and counting the number of times that they mention using the bus.

About this resource

This resource was first published in ‘Go Further: A practical guide to extended science projects’ in August 2015.

Go Further: A practical guide to extended science projects
Education levels:
16–19, Continuing professional development