The scales used a four-point rating system for each item. The score for
each scale was computed using the average of the responses to the items that
comprised the scale. Use of the average item response, as opposed to the summated
score, ensured that missing responses would not lead to a systematic negative bias
of the scale scores. A scale score was computed only for those respondents who had
valid responses for at least 75% of the items in the scale. If someone answered fewer
than 75% of a scale’s items, the respondent’s scale score was set to be missing and
omitted from that particular scale. The reliability of the obtained scale scores was
estimated using Cronbach alpha (a).