Testing of bagged items is a very sensitive method for detecting contamination.
To confirm mercury amalgamation, Shimada says, "would require an independent testing of items recovered from a nonfunerary context".
However, replicate jewelry pieces of some items showed tremendous variability in dilute HCl-extractable Cd despite comparable total Cd composition, suggesting the importance of doing replicate testing of items.
This study describes the design and testing of items for a self-completion questionnaire to be used within 16+ educational institutions to identify and measure the factors that influence the identification of students at HR for psychosis using TPB.
To develop the instrument, the URSSA was piloted and validated on multiple campuses with diverse samples of students through "think-aloud" interviews and preliminary statistical testing of items' validity and reliability.
Of the 69 tests of item correlation with a scale other than its own, 61 tests (88%) demonstrated item- discriminant validity.
Results of tests of item convergent validity, item discriminant validity, reliability, and floor and ceiling effects are presented in Table 4.
This difference was significant when calculated via a paired sample t-test of item facility across all items (t=-6.358 t=-6.358p<0.001).
The multitrait/multi-item correlation matrix also allows examination of the assumption that items are stronger measures of their hypothesized constructs than of other constructs (test of item discriminant validity).
In addition, principal components analysis factor loadings (>0.48) and tests of item convergent/discriminant validity (>0.39) supported this finding, thus further indicating that all items in each of the scales passed the criteria (Tables 3, 4 and 5).
