Data comes in two main forms, depending on its closeness to the event recorded. Data that has been observed, experienced or recorded close to the event are the nearest one can get to the truth, and are called Primary data. Written sources that interpret or record primary data are called Secondary sources, which tend to be less reliable. For example, reading about a fire in your own house in the newspaper a day after will give you less accurate information than what you gained by experiencing the event yourself. You will be more informed about the facts and these will not be distorted by someone else’s interpretation.
We are being bombarded with primary data all day. Sounds, sights, tastes, tactile things are constantly stimulating our senses. We also have instruments to measure what we cannot so accurately judge through our senses, such as clocks, barometers, business accounts etc. There are four basic types of primary data, distinguished by the way they are collected:
- Measurement – collections of numbers indicating amounts, e.g. voting polls, exam results, car mileages, oven temperatures etc.
- Observation – records of events, situations or things experienced with your own senses and perhaps with the help of an instrument, e.g. camera, tape recorder, microscope, etc.
- Interrogation – data gained by asking and probing, e.g. information about people’s convictions, likes and dislikes etc.
- Participation – data gained by experiences of doing things e.g. the experience of learning to ride a bike tells you different things about balance, dealing with traffic etc., rather than just observing.
The primary data are the first and most immediate recording of a situation. Without this kind of recorded data it would be difficult to make sense of anything but the simplest phenomenon and be able to communicate the facts to others. Primary data can provide information about virtually any facet of our life and surroundings. However, collecting primary data is time consuming and not always possible. Although more data usually means more reliability, it is costly to organize large surveys and other studies. Furthermore, it is not always possible to get direct access to the subject of research. For example, many historical events have left no direct evidence.
Secondary data are data that have been interpreted and recorded. Just as we are bombarded with primary data, we are cascaded with secondary data in the form of news bulletins, magazines, newspapers, documentaries, advertising, the Internet etc. The data are wrapped, packed and spun into concise articles or digestible sound bites. The quality of the data depends on the source and the methods of presentation. Refereed journals containing papers vetted by leading experts, serious journals, such as some professional and trade journals will have authoritative articles by leading figures. Magazines can contain useful and reliable information or be entirely flippant. The same goes for books. Television and radio programmes vary likewise, as does information on the Internet. A major aspect of using secondary data is making an assessment of the quality of the information or opinions provided. This is done by reviewing the quality of evidence that has been presented in the arguments, and the validity of the arguments themselves, as well as the reputation and qualifications of the writer or presenter. It is also good practice to compare the data from different sources. This will help to identify bias, inaccuracies and pure imagination. It will also show up different interpretations that have been made of the event or phenomenon.