Stats to show impact don’t have to be scary

World Statistics Day (20th October) had a theme of ‘Better Data, Better Lives’. Sector think-tank NPC used this to hang an article on statistical significance and control groups: ‘Impact or no impact? It’s a little more complicated than that…

“Charities often struggle to prove that they are making the impact that they exist to achieve. One way of proving this impact is to use data and statistics. By comparing a charity’s beneficiaries with a similar group of people who have not accessed that charity’s services (known as a ‘comparison group’), it is possible to see whether a charity’s work has achieved any kind of result. These results are judged by their statistical significance  – whether a causal link can be established between the charity’s work and outcomes for its beneficiaries.”

The sub-headings are:

  • Statistical insignificance can mean more research is needed
  • Economic significance is also important
  • Is the right outcome being targeted?
  • Does our comparison group benefit from other interventions?
  • How good a ‘match’ is our comparison group?

There is also a link to NPC’s recent publication, a short guide titled ‘Understanding statistical significance‘. Our earlier mention of this probably got lost amongst coverage of other data issues.