Abstract

An index of quality is a measurement like any other, whether it is assessing a website, as in today's BMJ ,1 a clinical trial used in a meta-analysis,2 or the quality of a life experienced by a patient.3 As with all measurements, we have to decide whether it measures what we want it to measure, and how well. The simplest measurements, such as length and distance, can be validated by an objective criterion. The earliest criteria must have been biological: the length of a pace, a foot, a thumb. The obvious problem, that the criterion varies from person to person, was eventually solved by establishing a fundamental unit and defining all others in terms of it. Other measurements can then be defined in terms of a fundamental unit. To define a unit of weight we find a handy substance which appears the same everywhere, such as water. The unit of weight is then the weight of a volume of water specified in the basic unit of length, such as 100 …

Keywords

Computer scienceData scienceStatisticsInformation retrievalMathematics

Affiliated Institutions

Related Publications

Publication Info

Year
2002
Type
article
Volume
324
Issue
7337
Pages
606-607
Citations
229
Access
Closed

External Links

Social Impact

Social media, news, blog, policy document mentions

Citation Metrics

229
OpenAlex

Cite This

John M. Bland (2002). Statistics Notes: Validating scales and indexes. BMJ , 324 (7337) , 606-607. https://doi.org/10.1136/bmj.324.7337.606

Identifiers

DOI
10.1136/bmj.324.7337.606