Quantitative and qualitative measurement
Quantitative research relies primarily on numbers as the main unit of analysis. It is more commonly used as a primary method in scientific and clinical research, such as drug trials or laboratory experiments where tests may need to be repeated many times, for example to ensure that a new drug is safe. Although quantitative methods, such as surveys, are used in educational research, the vast majority of research is relatively small scale, intensive, focused on change and involves human perceptions. Educational research relies much more heavily on qualitative methods. One of the most common instruments to gather numerical data in education (particularly in evaluation of programmes) is the questionnaire survey, using a series of closed questions to which responses are given against a Likert or other type of scale. Open questions can also be included to gather richer data. Large amounts of data can be gathered from a wide number of people and the results can be analysed by computer (either by an optical mark reader or through an online survey instrument such as ‘Survey Monkey’), thus making it fairly straightforward to research a large sample of respondents. Survey questionnaires can be given out and collected face to face, sent by post or posted online. If achieving a high response rate is important, then note that the less personal involvement there is with potential respondents, the lower the response rate. So, typically, online surveys may have a response rate of under 20%, whereas if the questionnaires are given out and collected face to face, you may achieve a very high response rate.
Qualitative research relies primarily on words as its unit of analysis and its means of understanding. However, it can also use voice tone, loudness, cries, sighs, laughs, and many other ways of human communication. The words may be spoken in individual interviews (face to face or on the telephone) or groups, or they may be written, so you may have to analyse the spoken words of an interview, focus group or conversations (for example between a patient and health worker), or the written words of an account or description or diary record.
On the whole, qualitative research tends to be small scale, simply because it is hugely labour intensive. For example, interviews or focus groups will usually need to be transcribed before they can be analysed. In addition, the researcher is often more involved with the person producing the words, and so it is sometimes helpful for others to conduct the analysis; again this can be costly. Having said that, nothing else can provide the same level of richness as qualitative data, and at the very least, adding space for respondents to provide some words to describe what might be otherwise gathered by numbers is immensely useful to the researcher, and may even, in some situations, be a help to the subject.
Qualitative methods range from the classification of themes and interconnections, content analysis, grounded theory and discourse analysis, and reliability and validity are just as important as they are in quantitative analyses. There are computer programs to assist in analysis, and although these might not necessarily save time, they often offer more systematic ways of coding data and identifying connections and themes.
Triangulation is the term used for bringing a number of research methods to bear upon a question. For example, to study the effect of threatened closure of a hospital on its staff you might want to interview a selected few at different levels and in different professions; a questionnaire survey of almost everyone; personnel data of sickness, absence, turnover, etc.; a network analysis of rumour; an ethnographic study of a long-stay ward looking at staff and patients interactions; and so on. A triangulation of methods such as these would provide an exceptional in-depth look at such an event, but it is also useful simply to combine some form of qualitative and quantitative data, as suggested above.