Collecting & Recording Data

It is important to recognise that different types of data can be collected in a scientific investigation,

Qualitative data

Qualitative data are descriptive and observed using the senses. Qualitative data cannot be counted or quantified. Observations of qualitative data can be made using descriptive words. For example, different textures can be described using the following adjectives: brittle, coarse, crumbly, dense, flexible, fluffy, glossy, gritty, jagged, prickly, wrinkly, rocky, rough, scaly, silky, slimy, smooth, spongy, springy, thorny or velvety. Remember qualitative → quality.

Quantitative data

Quantitative data are expressed in numbers and come from measuring or counting. The data are recorded using scientific measuring units, such as grams, centimetres, millimetres or degrees Celsius. Remember quantitative → quantity.

Discontinuous and continuous data

Quantitative data are also described as being discontinuous or continuous. Discontinuous or discrete data means the data are composed of categories and can only take a certain number of values. For example, shoes only come in set sizes, such as 7, 7.5, 8 and 8.5.

Continuous data can take any possible value in a given range. For example, feet come in a whole range of different lengths, so these data are continuous. Measurements of foot length are not set values in the same way that shoe sizes are.