Full details of the development of the ECOS can be found in Rose, Markland and Parfitt (2001). Following initial consensus validation work on the scenarios and responses, and a pilot study, a preliminary version of the ECOS comprising nine scenarios was completed by 592 adult respondents. The factorial validity of the scale was assessed using a multi-trait, multi-method approach. Specifically, a correlated-trait, correlated uniquenesses model was assessed using confirmatory factor analysis in LISREL 8.30.

ECOS conceptual model

Starting with a nine scenario model, scenarios were successively removed based on evidence of factorial ambiguity among the items to achieve the best-fitting model whilst maintaining optimum breadth of content. A seven-scenario model was eventually accepted. The fit of this model was: Satorra-Bentler scaled chi sq = 387; minimum fit function chi square = 445; df = 165; CFI = .96; SRMR = .06; RMSEA = .05 (90% confidence interval. = .04 : 06).

The intercorrelations among the orientations were as follows: