Significance and Use
4.1 Rating instruments or rating scales are commonly used in many areas such as sensory evaluation, marketing research, experimental psychology, survey research, and economics in which there is interest in quantifying perceptions such as liking, preference, level of purchase interest, intensity of an attribute, degree of difference, or level of agreement with statements. This guide is concerned with the scales that are used to record human responses to physical stimuli rather than measuring physical entities. Many types of rating scales already exist and have been used in the above fields. Specific rating scales each have their own properties, advantages, and disadvantages. Some rating scales are intended for specific applications, while others have broader applications. Some rating scales have been extensively studied and modeled and have well-established properties.
4.2 Given the overwhelming number of scales available to practitioners when designing research, it is necessary for the researcher to have some knowledge about the scales that are available along with the many considerations that surround their use and applications. This guide will be useful to the sensory researcher who wants to use a scale as a measuring tool for their work. Selecting the right scale is a critical step towards meeting the research objective and making valid conclusions.
1.1 The objective of this guide is to provide information to be reviewed and considered by the sensory and consumer scientist who wants to select and use scales to measure responses from consumers or trained assessors. For ease of reading, the term sensory scientist is used throughout the guide when statements apply to the sensory and consumer scientists.
1.2 This guide covers a brief definition of scales as well as some fundamental and practical challenges the sensory and consumer scientists should be aware of when using scales. It also provides a list and a description of the most commonly used scales in the field of sensory evaluation and consumer product research along with a classification framework for these scales.
1.3 The scope of this guide is limited to the sensory and consumer science professional’s selection and use of rating scales when an assessor assigns one symbol/value to one stimulus, to their perception of a stimulus or an internal attitude/opinion. It does not cover:
1.3.1 Details of analysis of data obtained from rating scales,
1.3.2 Guidelines for questionnaire design including attribute selection,
1.3.3 Fundamentals of measurement such as reliability and validity,
1.3.4 Measurement models used to convert scale responses into measures of unobserved sensory or hedonic quantities,
1.3.5 Tasks in which the assessor assigns a symbol/value to a group of stimuli,
1.3.6 Rankings, and
1.3.7 Multi-item scales.
1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.