These can Sirolimus in vitro be calibrated and then used with confidence to measure and quantify attributes such as competence in physiotherapy practice ( Bond and Fox 2007). This conversion facilitates appropriate interpretation of differences between individuals and tallying of converted scores provides interpretable total scores. Functioning of items: In this study the construct of interest was competence to practice physiotherapy.

If scores for items fit a Rasch model, a number of qualities should be evident in the data. Items should present a stable hierarchy of difficulty. It should be easy to achieve high scores on some items and difficult on others, with items in-between ranking in a reliable way. An instrument with these properties would make the user confident that a student who achieved a AZD5363 research buy higher total score was able to cope with the more difficult, as well as the easier, challenges. Educators could identify challenging items and appropriate educational support could be developed to help students achieve these more challenging targets. Item bias: A scale that fits a Rasch model should function consistently irrespective of

subgroups within the sample being assessed. For example, male and female students with equal levels of the underlying construct being measured should not be scored significantly differently ( Lai et al 2005). Rasch analysis enables assessment of item bias through investigation of Differential Item Functioning. In the development Olopatadine of the APP, the research team was particularly interested to determine whether the scale performed in a comparable way regardless of the student’s age, gender, or the total number of weeks of clinical experience, the educator’s age, gender, or experience as an educator, the type of facility where the clinical placement occurred, the university that delivered the student’s education, or the clinical

area. Dimensionality: One of the primary tenets underpinning Rasch analysis is the concept of unidimensionality. If the scale scores on each item of the APP are to be added together to provide a total score representing an overall level of professional competence, Rasch analysis should indicate a scale that is unidimensional, a scale that measures one construct. Unidimensionality was explored using the independent t-test procedure ( Tennant and Pallant 2006). Targeting of instrument: It is important, particularly in clinical practice, that the assessment items are appropriately targeted for the population being assessed. Poorly targeted measures result in floor or ceiling effects, and this would mean that either very weak or very strong students may not be graded appropriately. Rasch modeling provides an indication of the match between the item difficulty and the abilities of people in the sample. A well-targeted scale would have a mean person location around zero ( Tennant and Conaghan 2007).