BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Introduction to Mokken scaling - Professor John Rust (University o
 f Cambridge)
DTSTART:20091203T103000Z
DTEND:20091203T113000Z
UID:TALK21094@talks.cam.ac.uk
CONTACT:Michal Kosinski
DESCRIPTION:This session will demonstrate how to use links to downloads th
 at enable various psychometric analyses to be carried out in Stata. Detail
 s on these the links appear in The Psychometrics Centre website. One of th
 ese is Mokken scale analysis\, a non-parametric hierarchical scaling metho
 d similar to Guttman scaling. Both techniques assume the existence of an u
 nderlying latent (unobservable) attribute\, which is represented by a set 
 of items that are ordered in terms of difficulty and related to a latent a
 ttribute. Both imply that any individual who agrees with a particular item
  will also agree with all the items ranked lower in difficulty. The main d
 ifference between Guttman scaling and Mokken scaling is that Mokken scalin
 g has a probabilistic nature whilst Guttman scaling does not. In Mokken sc
 ale analysis reproducibility is measured by Loevinger's coefficient Hi for
  each item and H for the entire scale. The calculation of Hi and H depend 
 on comparing the probability of errors in ranking to the probability of su
 ch a ranking occurring if the items are unrelated. Hi and H will take valu
 es between 0 and 1. A commonly used rule of thumb is that a strong scale i
 s one in which all Hi and H exceed 0.5 in value. Items can be omitted from
  a scale items if they have low value of Hi\, hence it is a straightforwar
 d non-parametric approach to item analysis within test construction.
LOCATION:Seminar Room\, The Mond Building\, New Museums Site
END:VEVENT
END:VCALENDAR