Principal components analysis indicated a 13-item scale (items loading >0.39) with satisfactory internal consistency reliability (α = 0.77), although neither this model nor any alternatives were confirmed in the confirmatory factor analysis.
After exploratory factor analysis on first year student responses (55.76% variance explained) and confirmatory factor analysis on second year responses, a 5-factor model consisting of 14 items was obtained with satisfactory model fit (χ (66)=112.83, p<0.001, RMSEA=0.06, CFI=0.91) and nesting between year groups (Δχ(7)=3.079, p=0.878).
The test-retest showed that MSPSS produced item and scale scores with satisfactory reproducibility.
Although a uni-dimensional scale could not be confirmed using CFA, exploratory analyses supported a 13-item uni-dimensional scale (with satisfactory reliability), consistent with the findings of the US validation [ 13].
As we excluded item 12 and recalculated EFAs, loadings of remaining items stayed satisfactory with highest loadings equal to or above 0.45 on factors indicated by theory in both solutions.
A six-factor oblique model with an additional factor loading reverse-worded items provides satisfactory fit with the data (RMSEA = 0.077, TLI = 0.860, CFI = 0.905).
This process lead to a 5-item version of the NDI with satisfactory indicators of location dependence and unidimensionality (4.6% significant t-tests, mean residual correlation of 0.19, range 0.08 to 0.33).
The difficulty factor for most of the items was satisfactory (0.14-0.92) with a mean SD) of 0.74 0.21).
This multi-step process resulted in a 21-item, seven-point Likert-type instrument with satisfactory construct validity, which is based on a multi-leveled model of immersion with multidimensionality in each level.
The scale of 17 items exhibited satisfactory internal consistency with Cronbach's α coefficient of reliability measuring 0.80.
