### What is quantitative data?

Data can be described as quantitative if it can be measured or identified on a numerical scale. Examples include length, height, area, volume, weight, speed, age, distance, cost and so on. However, not all data using numbers is quantitative: Datasets are often classified into categorical data, i.e. using numbers as descriptors. Arithmetic performed on the numbers describing categorical data would produce nonsensical results, for the same reason that you cannot add 6 Acacia Road to 12 Acacia Road to create 18 Acacia Road.

Be wary, therefore, when you consider a dataset. What exactly do the numbers represent? If your numbers answer a question beginning ‘how many’ or ‘how much’, you have quantitative data. If your numbers represent groups or classes, you have qualitative data expressed categorically. The appropriate analytical techniques will vary accordingly.

A quantitative approach can be useful for understanding many of the problems faced by researchers in the arts and humanities: Numerical data can describe change over time or space; enable linguistic analysis; underpin archaeological investigation; in fact it can illuminate, at least to some degree, any human process. However, a dataset is always an abstraction from the ‘real’ world and, as such, the skills of humanities researchers can provide a vital critical perspective on their use. Quantitative data can describe, but it takes a person to explain. You might therefore want to supplement a quantitative analysis with qualitative research and case studies. Or you might take a quantitative approach to find out how representative of the wider world your case studies are.

Quantitative data can come from all sorts of sources including scientific instruments, social questionnaires and clinical trials but for many humanities research datasets the provenance is a step removed from the source. Historical research, for example, usually relies on archival work and can involve simply counting instances in the records. Such work has been made easier by the digitisation of much useful material including government and legal records and printed works dating back centuries, though this digitisation has barely made a dent in the totality of potential sources.