Market research glossary

An interviewing method that explores the underlying motivations behind consumer decisions by repeatedly asking “why”. This technique uncovers the deep-seated values and drivers behind purchase behaviour.

Length of interview (often abbreviated to LOI) is the time taken for a market research session to be completed. The terminology dates back to the time when all market research interviews (qualitative and quantitative) involved a human interviewer, but nowadays it is also applied to self-service methodologies, such as online surveys.

A type of Rating scale survey question where respondents are asked to state the extent to which they agree of disagree with a series of statements (e.g. strongly agree, slightly agree, neither agree nor disagree, slightly disagree, strongly disagree). The scale is named after its inventor, American psychologist Rensis Likert (1903-1981). Traditionally, Likert scales have an odd number of possible answers, leaving a neutral position in the middle, but in market research they can include an even number of possible answers instead, forcing respondents to decide which side of the middle they are on. The term Likert scale is often used to describe other types of rating scale as well.

Longitudinal market research monitors changes in respondents’ perceptions, behaviour or demands over time. A longitudinal study may observe the same group of people for a protracted period, in which case it is called a cohort study. The participants will often have a key characteristic in common.