Blog

Oct
2019

Approaches to Model Validation

Part of the expertise involved in a useful piece of analysis is the ability to perform model validation. Model validation gives us a way to tell how useful our model is. Can we can trust what it tells us in terms of its predictions and its interpretation?

read more
Sep
2019

Assessing Questionnaire Validity

Questionnaire surveys are measurement instruments. While scientific measurement instruments measure physical properties like velocity or weight, questionnaire surveys often measure respondents' self-reported attitudes, opinions or behaviours. As with scientific measurement instruments, two important qualities of surveys are consistency and accuracy. These are assessed by considering the survey’s reliability and validity - in this blog we consider validity.

read more
Aug
2019

Embracing Uncertainty

There is currently much debate amongst professional statisticians on the topic of ‘statistical significance’ and the use of p-values. In this blog we discuss the risks in the over-use of and over-reliance on statistical significance testing, and the benefits in embracing uncertainty.

read more
Jul
2019

Data Visualisation with R’s ggplot2 Package

Google, Pfizer, Lloyds of London and Shell all use R to analyse and present their data. More recently, the BBC News’ Visual and Data Journalism team have also moved to using R’s ggplot2 package for their production-ready graphics for the BBC News website.

read more
Jun
2019

Novel Educational Research using Longitudinal Survey Data

A recent article in the Guardian newspaper reports on a study published last month that looks at parents' responses to news from the Ofsted inspection of their child's school. Aside from the eye-catching headline, we found a number of aspects of this study interesting.

read more
May
2019

Assessing Questionnaire Reliability

Questionnaire surveys are a useful tool used to gather information from respondents in a wide variety of contexts. We invariably use surveys because we want to measure something, for example, how frequently people exercise, voting intentions, the percentage of your customers that would recommend you to a friend. As such surveys can be viewed as a measurement instrument of, for example, behaviours, attitudes and opinions. Two important qualities of surveys, as with all measurement instruments, are consistency and accuracy. These are assessed by considering reliability and validity - in this blog we consider reliability.

read more