What is the difference between quantitative and qualitative research?

Quantitative research is concerned with measurement of a market and includes the calculation of market size, the size of market segments, brand shares, purchase frequencies, awareness measures of brands, distribution levels etc. Such quantitative data is required to some level of accuracy (though not in all cases to very high levels) and the methods used must be capable of achieving this.

Qualitative information is rather harder to define but the emphasis is on 'understanding' rather than simple measurement – Advert A is recalled better than Advert B (quantitative information), but how does A work as an advert and why is it more effective than B? Much qualitative research is concerned with empathizing with the customer and establishing the meanings he or she attaches to products, brands and other marketing objects. Another focus is motivation. For example, why does one product rather than another meet customer needs and what are these needs that are being met? Qualitative research is conducted amongst a sample but in this case usually a small one since there is no attempt to extrapolate to the total population. In the case of attitudes to brands, for example, qualitative research may determine that there is a specific view held about the brand whereas quantitative research would tell us what proportion holds that view.

Quantitative and qualitative research is often complementary and in a research design both may feature. The qualitative element frequently takes place at the front end of the study exploring values that need measuring in the subsequent quantitative phase. The “qual” research may offer a diagnostic understanding of what is wrong, while the “quant” research provides hard data across different respondent groups that can lead to specific recommendations with measures that can be used as controls to determine the effectiveness of actions.