Although we trained on and pre-tested our scales, we do not know the extent of item discrimination, which lends an additional unknown quantity of error to our results.
Finally, we assessed the acceptability of the questionnaires by calculating the extent of missing items within each HRQL instrument.
An important focus of research has been the extent of differential item functioning (DIF) in this item bank, i.e., the variation of item difficulty across different patient populations, which can be a relevant source of biased PRO scores.
1. Do not use in recording the extent of the item in the case of music.
9 Also, we have no objective data regarding whether an individual questionnaire respondent did, in fact, attempt to contact the out of hours GP service within the relevant time period, therefore we were unable to ascertain the extent of individual item "missingness" with regard to the out of hours questions within the overall questionnaire.
There were three items in the Extent of Participation scale, six items in the Perceived Limitations scale, and one item in the Satisfaction with Participation scale with ICCs below 0.5 (Table 3) Summary scores were equivalent by mode and that there was no evidence of an ordering effect (Table 4).
The internal consistency measured using Cronbach's alpha is influenced by the extent of covariation among the items and by the number of items in the scales [ 49, 51].
Regarding the extent of the impact (number of items with always/often answers), the average at baseline was 0.82 and upon follow-up was 0.26 (p = 0.05, Wilcoxon test).
The present volume is devoted primarily to demonstrating the scope of the national censuses and the extent of countries'participation in the items proposed in FAO's Programme for the 1960 World Census of Agriculture.
We also investigated each of the five main items to determine the extent of the risk of diabetes for each item separately.
The SIBTEST procedure can be used to determine the extent of the DIF, and classify items as having either negligible (A-level) DIF, moderate (B-level) DIF, or large (C-level) DIF (Roussos and Stout 1996b).
