||K10 and K6 Scales|
The K10 and K6 scales were developed with support from the U.S. government's
National Center for Health Statistics for use in the redesigned U.S. National
Health Interview Survey (NHIS). As described in more detail in Kessler et
al. (2003), the scales were designed to be sensitive around the threshold
for the clinically significant range of the distribution of nonspecific
distress in an effort to maximize the ability to discriminate cases of serious
mental illness (SMI) from non-cases. A small validation study carried out
in a convenience sample in Boston found evidence that the scales perform
quite well and that, in fact, the six-question scale is at least as sensitive
as the ten-question scale for the purpose of discriminating between cases
and non-cases of SMI. The K6 is now included in the core of the NHIS as
well as in the annual National Household Survey on Drug Abuse. The K10 is
in the Australian and Canadian equivalents of the NHIS. The K10 is also
included in the National Comorbidity Survey Replication (NCS-R) as well
as in all the national surveys in the World Health Organization's World
Mental Health (WMH) Initiative. We plan to refine the calibration rules
for the scales based on analysis of data in these surveys. At the moment,
though, the only calibration data come from the Boston validation study.
This web site will post information on expanded calibration as these data
Two versions of the scales are presented here, one for interviewer-administration and the other for self-administration. Note that the K6 is merely a truncated form of the K10 in which four questions are deleted. The question series presented here include not only the six or ten Likert scale questions in the scales, but also a number of other questions that we routinely administer along with the scales to learn about persistence and impairment. These additional questions are not required to score the K6 or K10.
Kessler, R.C., Barker, P.R., Colpe, L.J., Epstein, J.F., Gfroerer, J.C., Hiripi, E., Howes, M.J, Normand, S-L.T., Manderscheid, R.W., Walters, E.E., Zaslavsky, A.M. (2003). Screening for serious mental illness in the general population. Archives of General Psychiatry, 60(2), 184-189.
Copyright © World Health Organization 2003
The translations of the K6 and K10 are posted for unrestricted use, with the same requirement to acknowledge the WHO copyright and cite the above article.
Scoring Rules: click here.
For a comprehensive list of articles on the K10 and K6, click here.
All versions of the K6 and K10 are available for download on our website.
Translated versions of the K6/K10 instruments:
*Not yet translated in this language.
Are you interested in translating and using the K10/K6 in a language other than English?
Researchers and clinicians from a number of countries have contacted us about translating and validating the K10/6 in their languages. We will post each such translation on our web page when we receive it along with an acknowledgement to the person or persons who made the translation and a citation to any publication that reports the results of the validation. This memo provides a brief overview of requirements for acceptable translations and validations.
The 10 questions in the basic form of the K10 are included in the WHO World Mental Health surveys. These surveys are being carried out in 30 countries around the world and the interview schedule is being translated into 35 different languages. Some, but not all, of the collaborators in the WMH surveys are also translating the K10/K6 self-administration forms into these same languages. We are posting these versions as they become available. For those of you who are interested in translating the K10/6 self-administration forms into your language, we are using the WHO-CIDI translation protocol for all official K10/K6 translations. Please write and ask us for this protocol. We can then tell you if we already have another group working on a translation in your language and, if not, we can discuss with you a time line for your translation.
K10/K6 validations are being done in primary care clinics, community mental health centers, and social welfare offices. The validation standards differ in each case, but our preference is for validation to be based on a semi-structured research diagnostic interview, such as the SCID, and to have a sufficient number of respondents validated to have the statistical power needed for evaluation. A minimal design would be to carry out a clinical evaluation of 50 people who have a positive K6 score (10 or more on the 0-24 scale) and 50 who have a score in the range 0-9, although larger numbers would be better. The clinical re-interview should be carried out within 2 days of the K6 to make sure respondents are referring to the same 30-day recall period. Clinical interviewers should be blinded to K6 scores. Psychometric analyses of operating characteristics should be based on weighted data that adjust for the over-sampling of K6 positives in the sampling of clinical reappraisal respondents. This weighting is critical, as estimates of sensitivity, specificity, and AUU would be biased in the absence of weighting.
To contact us about K10/K6 translation and validation, email email@example.com.
Frequently Asked Questions
Q. Has the scale been used in surveys of racial and