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Mokken Scale Procedure

mspvarlist[,nodetailskernel(#)c(#)notestp(#)pairwiseminvalue(#)nobonnoadjust]

varlistis a list of two existing dichotomous or polytomous variables or more.

Description

mspselects scales of dichotomous or polytomous items with the Mokken Scale Procedure (MSP) defined by Mokken (1971) and by Hemker and al. (1995).

Options

nodetailsdoes not display informations during the algorithm of selection.

kerneldefines a kernel for the first scale, defined as the first # items ofvarlist.

cdefines the level of the thresholdc. The level ofcis fixed, by default, at 0.3.

notestselects the scales whithout tests among the Loevinger H coefficient (Hjk>0): the new item with the maximal value for Hj>c is always selected.

pdefines the significance level for the tests. The level ofpis fixed, by default, at 0.05.

pairwisedoes no more delete all the individuals who have one or more missing values among all the items ofvarlistbut, only these ones who have, for each pair of items, one or more missing values to these two items.

minvaluedefines the minimum value of the coefficient Hjk for a pair of item composing a scale. This minimal value is fixed by default to 0.

nobondoes no more correct the significance level of the test by the Bonferroni correction.

noadjustapproximates the tests statistics like the MSP program (Molenaar et al. (2000)).

RemarksFor detailed informations on the Mokken scale procedure, see Mokken (1971), Hemker and al. (1995) or the manual of the MSP software (2000).

mspruns with dichotomous or polytomous items.

mspnecessitates the program loevh to compute.

Results

r(dim)saves the number of built scales.

r(selection)saves a vector which contains, for each item, the scale where it is selected (0 if the item is unselected).

r(H#)saves the Loevinger's H coefficient of the #th scale.

r(nbitems#)saves the number of items selected in the #th scale.

r(scale#)saves the names of the items selected in the #th scale.

r(scalenum#)saves the numbers of the items selected in the #th scale.

Example. msp itemA1-itemA7

. msp itemA* itemB* , nodetails kernel(2)

. msp item* , c(0.2) nob pairwise

ReferencesHemker B. T., Sijtsma K. and Molenaar I. W., Selection of unidimensional scales from a multidimensional item bank in the polytomous Mokken IRT model,

Applied Psychological Measurement, vol.19(4), 1995, pp. 337-352.Mokken R. J., A theory and procedure of scale analysis. New-York/Berlin : De Guyter, 1971.

Molenaar I. W., Sijtsma K. and Boer P. User's manual of MSP5 for Windows. Groningen (The Netherlands): iec ProGAMMA, 2000.

Also seehelp for loevh (if installed), help for mokken (if installed)

AuthorJean-Benoit Hardouin, PhD, assistant professor EA 4275 "Team of Biostatistics, Clinical Research and Subjective Measures in Health Sciences" University of Nantes - Faculty of Pharmaceutical Sciences 1, rue Gaston Veil - BP 53508 44035 Nantes Cedex 1 - FRANCE Email: jean-benoit.hardouin@univ-nantes.fr