Skip to content Skip to navigation
University of Warwick
  • Study
  • |
  • Research
  • |
  • Business
  • |
  • Alumni
  • |
  • News
  • |
  • About

University of Warwick
Publications service & WRAP

Highlight your research

  • WRAP
    • Home
    • Search WRAP
    • Browse by Warwick Author
    • Browse WRAP by Year
    • Browse WRAP by Subject
    • Browse WRAP by Department
    • Browse WRAP by Funder
    • Browse Theses by Department
  • Publications Service
    • Home
    • Search Publications Service
    • Browse by Warwick Author
    • Browse Publications service by Year
    • Browse Publications service by Subject
    • Browse Publications service by Department
    • Browse Publications service by Funder
  • Help & Advice
University of Warwick

The Library

  • Login
  • Admin

Modelling health scores with the skew-normal distribution

Tools
- Tools
+ Tools

Hutton, Jane and Stanghellini, E. (2009) Modelling health scores with the skew-normal distribution. Working Paper. Coventry: University of Warwick. Centre for Research in Statistical Methodology. Working papers, Vol.2009 (No.39).

[img]
Preview
PDF
WRAP_Hutton_09-39w.pdf - Published Version - Requires a PDF viewer.

Download (695Kb)
Official URL: http://www2.warwick.ac.uk/fac/sci/statistics/crism...

Request Changes to record.

Abstract

Health care interventions which use quality of life or health scores often provide data
which are skewed and bounded. The scores are typically formed by adding up responses
to a number of questions. Different questions might have different weights, but the scores
will be bounded, and are often scaled to the range 0 to 100. If improvement in health
over time is measured, scores will tend to cluster near the 'healthy' or 'good' boundary
as time progresses, leading to a skew distribution. Further, some patients will drop out
as time progresses, so the scores reflect a selected population.
We fit models based on the skew-normal distribution to data from a randomised controlled trial of treatments for sprained ankles, in which scores were recorded at baseline
and 1, 3 and 9 months. We consider the extent to which skewness in the data can be
explained by the clustering at the boundary via a comparison between a censored normal
and a censored skew-normal model.
As this analysis is based on the complete data only, a formula for the distortion of
the treatment effects due to informative drop-out is given. This allows us to assess under
which conditions the conclusions drawn on the complete data may be either reinforced or
reversed, when the informative drop-out process is taken into account.

Item Type: Working or Discussion Paper (Working Paper)
Subjects: Q Science > QA Mathematics
Divisions: Faculty of Science, Engineering and Medicine > Science > Statistics
Library of Congress Subject Headings (LCSH): Medical care -- Statistics
Series Name: Working papers
Publisher: University of Warwick. Centre for Research in Statistical Methodology
Place of Publication: Coventry
Official Date: 2009
Dates:
DateEvent
2009Published
Volume: Vol.2009
Number: No.39
Number of Pages: 13
Institution: University of Warwick
Status: Not Peer Reviewed
Access rights to Published version: Open Access
Funder: Engineering and Physical Sciences Research Council (EPSRC), Great Britain. Dept. of Health (DoH), University of Warwick. Centre for Research in Statistical Methodology, Italy. Ministero dell'istruzione, dell'università e della ricerca (MIUR)
Grant number: 01/14/10 (DoH), PRIN 2007XECZ7L−003 (MIUR)

Request changes or add full text files to a record

Repository staff actions (login required)

View Item View Item

Downloads

Downloads per month over past year

View more statistics

twitter

Email us: wrap@warwick.ac.uk
Contact Details
About Us