These analyses revealed that item-level differences minimally affected item-set alcohol abuse estimates.
These item-level differences did not affect alcohol abuse estimates based on the set, though.
Sensitivity analyses indicated that item-level differences did erroneously impact alcohol abuse rates in 2001 2002, underestimating rates among Hispanics relative to Caucasians.
Given similar item-level differences for the " trouble[s] with family and friends" and " legal problems" items at 1992 and 2001 2002, health care interventions and clinicians should pay particular attention to these two criteria.
Examination of item-level differences using a Wilcoxon signed rank test revealed significant differences only for the "Numbness, Tingling, Burning Sensation, or Pain" item (z = −4.438, p < 0.001) with a small effect size (ρ = .23) and mean difference of 1.6 points (SD: 1.1).
Items 1, 3, 9 and 12 were observed in at least 50% of the consultations in the UC group, while the EAP group had scores of at least 50% for items 1, 3, 4, 5, 9, 11, and 12. On item-level, a difference of 40% or more in favor of the EAP group was observed for the items 4, 5, and 9.
The differences on item-level show, that individuals with managerial function might be well suited to act as champions in a checklist implementation program as they, on an average level, value the checklist higher and feel more able to implement it.
Impact analyses have also been used to investigate whether item-level DIF results in clinically important differences at the scale level [ 77].
Graff et al 2 defined 20% improvement as being clinically relevant, which is indicated by a pre post-treatment difference of 0.8 on item-level.
This last step ensures that group (or time-related) differences obtained from comparisons of item composite scores (i.e., summing and averaging across individual items) can be attributed to substantive differences on the construct and are not due to differences in proportion of error variance in item-level scores.
Missing item-level data are commonly reported.
