Page 41 - Balancing between the present and the past

Beyond face validity, we wanted to test the instruments for accuracy, so we invited 10
professional historians to complete the measures. We calculated mean item scores
for all three categories using a 4-point scale.2 The expert scores on the historical contextualization items were 3.93 (Nazi Party) and 3.87 (slavery); those for the role 2 of the historical agent items were 3.87 (Nazi Party) and 3.63 (slavery). The scores on
the present-oriented perspective items (using a reverse-coding scheme, in contrast to the role of the historical agent items and historical contextualization items) were 3.83 (Nazi Party) and 3.83 (slavery). As we expected, the experts scored the role of the historical agent and historical contextualization items high and did not reason from a present-oriented perspective.
In accordance with these findings and to refine our content validity results, we derived two hypotheses, in which we predicted higher HPT scores among (1) older students and (2) students with more topic knowledge. The mean student score (on a 4-point scale) for the Nazi Party prior-topic knowledge test was 2.77 compared to 2.10 for the slavery prior-topic knowledge test. We calculated the correlation of students’ total HPT scores with their ages and their prior topic knowledge scores. The results appear in Table 2.
Table 2. Correlations of student HPT scores with age and prior knowledge (N = 1,270) Nazi Party .35* .27*
Slavery .21* .24*
Note. *Correlations are significant at the .01 level.
2.5.2 Dimensionality and internal consistency of both instruments
The principal component analysis (PCA) served to examine the structure of our data collected using our instruments. In line with Hartmann and Hasselhorn (2008), we expected to find two dimensions: one representing the two poles of a present-oriented perspective vs. a historical contextualization and the other representing the role of the historical agent. The results of the PCA for the Nazi Party instrument in Table 3 reveal two factors extracted with eigenvalues greater than 1. They accounted for 42% of the variance (factor 1: 28%, factor 2: 14%). The factor loadings after Varimax rotation
2 The published article (Huijgen, Van Boxtel, Van de Grift, & Holthuis, 2014) described the wrong expert scores. The scores on the historical contextualization items were not 3.88 (Nazi Party) and 3.77 (slavery) but 3.93 and 3.87, respectively. The scores on the role of the historical agent items were not 3.56 (Nazi Party) and 3.23 (slavery) but 3.87 and 3.63, respectively. The scores on the present-oriented perspective items were not 3.93 (Nazi Party) and 3.89 (slavery) but 3.83 and 3.83, respectively.
Measuring historical contextualization
Instrument
Age
Prior knowledge
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