Table 3

Reliability (homogeneity)

Subscales and itemsCorrected item–total correlations for subscale itemsCronbach's α: if item deleted from six-item subscaleMean/SD (range 5–30 (five-item response categories×six items per subscale: range of subscale: 6–30))% floor (positive end scores)% ceiling (negative end scores)Skewness (skewness: symmetry of distribution normal=0)
Medication subscaleSubscale: 0.715Subscale: 14.853/3.4610.632
4. “The side effects of medication are worse than those from angioplasty”0.4080.6883.33/0.820830.157
8. “Having to carry medication when outside the home would be troublesome”0.4400.6793.79/0.9381820.981
16. “With medication, the side effects are often worse than the condition”0.5360.6492.50/0.9091120.415
37. “Organising regular prescriptions with any medication can be a nuisance”0.4470.6783.64/0.9981340.967
44. “The side effects of medication are worse than those from surgery”0.4480.6803.37/0.712410.111
48. “Most medication is very difficult to understand”0.4260.6843.41/1.003750.747
Angiography subscaleSubscale: 0.769Subscale: 15.961/3.578−0.220
25. “Overall, angioplasty is a good thing”0.5580.7302.29/0.69412<1−0.103
28. “The balance of risks and benefits of angioplasty seem better than the risks and benefits of medication”0.4740.7442.79/0.81861−0.124
32. “People who have angioplasty seem to do well”0.5090.7432.44/0.6176<1−0.546
39. “Angioplasty is a last resort”0.4130.7672.91/1.04869−0.100
45. “I'm too old to have angioplasty”0.5780.7183.32/1.081137−0.349
52. “I'd put off having angioplasty”0.6360.6993.30/0.97093−0.196
Surgery (CABG) subscaleSubscale: 0.774Subscale: 15.121/3.357−0.298
2. “Surgery would prolong my life”0.5340.7372.61/0.903132−0.100
30. “Overall surgery is a good thing”0.6300.7132.48/0.8111010.188
36. “The balance of risks and benefits of surgery seem better than the risks and benefits of medication”0.5140.7122.92/0.85162−0.230
43. “Surgery gets the treatment over with quickly”0.6060.7182.53/0.815910.121
46. “I would have surgery if I could avoid being a burden on others in the long term”0.3740.7802.27/0.8861810.551
47. “People who have surgery seem to do well”0.4930.7492.31/0.666101−0.278
  • CABG, coronary artery bypass graft.

  • Codes were reversed for negative questionnaire items throughout so positive responses=lowest and negative responses=highest scores.