Primary and Secondary Data
Primary data is data collected by a person or organisation as a result of a survey, census or test of some sort.
Collection primary data can be time consuming and expensive, but it has several important advantages.
The collection method can be tailored to the purpose.
The accuracy of the data is easier to assess.
Primary data often needs to be collected by companies deciding on possible demand for a new product, or the location of a new store.
Secondary data is data not collected by or on behalf of the person who is going to use it. Often these days, data can be looked up on the internet. The person or organisation using the data has no direct connection with the gathering of the data.
A lot of government data is freely piublished and widely available. These include census surveys and economic surveys. Public opinion polls also tend to be made freely available. Seconday data is especially convenient if it comes as a spreadsheet, because it is then easy to use and analyse.
Seconday data is often publisehed regularly, allowing trends to be analysed.
Secondary data is cheap – often free – and widely available, but has several disadvantages.
The collection method may not be known and the accuracy of the data can be hard to assess. It can be especially hard to account for bias.
It may come in a hard to handle form. If a survey is in the form of worded answers, the data is not easy to manipulate.