In our experience, the Mokken model appears to be less well-known than for example the (related) Rasch model, but is seeing increasing Daporinad cell line use in contemporary clinical research and public health. Mokken’s method is a generalisation of Guttman scaling that can assist in the determination of the dimensionality

of tests or scales, and enables consideration of reliability, without reliance on Cronbach’s alpha. This paper provides a practical guide to the application and interpretation of this non-parametric item response theory method in empirical research with health and well-being questionnaires.

Methods: Scalability of data from 1) a cross-sectional health survey (the Scottish Health Education Population Survey) and 2) a general population birth cohort I-BET-762 solubility dmso study (the National Child Development Study) illustrate the method and modeling steps for dichotomous and polytomous items respectively. The questionnaire data analyzed comprise responses to the 12 item General Health Questionnaire, under the binary

recoding recommended for screening applications, and the ordinal/polytomous responses to the Warwick-Edinburgh Mental Well-being Scale.

Results and conclusions: After an initial analysis example in which we select items by phrasing (six positive versus six negatively worded items) we AZD1152 inhibitor show that all items from the 12-item General Health Questionnaire (GHQ-12) – when binary scored – were scalable according to the double monotonicity

model, in two short scales comprising six items each (Bech’s “”well-being”" and “”distress”" clinical scales). An illustration of ordinal item analysis confirmed that all 14 positively worded items of the Warwick-Edinburgh Mental Well-being Scale (WEMWBS) met criteria for the monotone homogeneity model but four items violated double monotonicity with respect to a single underlying dimension.

Software availability and commands used to specify unidimensionality and reliability analysis and graphical displays for diagnosing monotone homogeneity and double monotonicity are discussed, with an emphasis on current implementations in freeware.”
“The solid phase polymerase chain reaction (PCR) on a gel-based microarray system was studied under various durations of individual stages of the PCR cycle and spatial restriction of the reaction volume. Combining the experimental study with numerical modeling, we demonstrated that the diffusion of the PCR product in and out of a microarray element during the annealing and melting stages, respectively, is the main factor responsible for distinctive features of the studied type of PCR. The restriction of reaction volume leads to faster PCR signal growth.