Table 2.

Agreement statistics for estimated hours spent outdoors in the summer during 9:00 a.m. and 3:00 p.m. among 124 U.S. radiologic technologists from two geographic regions, according to the type of questionnaire

NTime-based questionnaire
Activity-based questionnaire
P*
Agreement (%)κ (95% CI)Agreement (%)κ (95% CI)
Total population
Weekdays
    Ages 0-1212152.90.36 (0.23-0.50)49.20.28 (0.15-0.40)0.34
    Ages 13-1912251.20.43 (0.31-0.55)47.20.36 (0.25-0.49)0.48
    Ages 20-3912137.70.15 (0.03-0.28)47.20.40 (0.28-0.51)0.008
    Ages 40-6412245.10.26 (0.13-0.38)51.60.42 (0.30-0.54)0.06
    Ages 65+3339.40.38 (0.16-0.60)52.90.48 (0.25-0.70)0.65
Weekend days
    Ages 0-1211859.20.38 (0.24-0.53)54.90.33 (0.21-0.45)0.58
    Ages 13-1911959.20.50 (0.39-0.61)48.80.31 (0.20-0.43)0.02
    Ages 20-3912052.50.42 (0.30-0.55)52.00.30 (0.18-0.42)0.12
    Ages 40-6411847.90.38 (0.27-0.49)43.90.40 (0.28-0.52)0.88
    Ages 65+3336.40.33 (0.11-0.55)47.10.37 (0.12-0.63)0.81
Female
Weekdays
    Ages 0-126448.40.28 (0.10-0.46)42.20.17 (0.00-0.35)0.17
    Ages 13-196448.40.35 (0.18-0.53)40.60.21 (0.04-0.37)0.27
    Ages 20-396439.10.17 (0.00-0.35)54.70.37 (0.20-0.54)0.18
    Ages 40-646443.80.10 (0.00-0.28)54.70.37 (0.20-0.55)0.04
    Ages 65+1566.70.40 (0.06-0.74)60.00.10 (0.00-0.61)NA
Weekend days
    Ages 0-126457.80.37 (0.17-0.56)53.10.38 (0.22-0.54)0.93
    Ages 13-196352.40.41 (0.24-0.58)47.60.23 (0.03-0.40)0.14
    Ages 20-396445.30.37 (0.21-0.53)54.70.48 (0.31-0.64)0.32
    Ages 40-646342.90.30 (0.15-0.45)57.10.45 (0.29-0.61)0.13
    Ages 65+1546.70.26 (0.00-0.60)80.00.68 (0.33-1.00)0.49
Male
Weekdays
    Ages 0-125759.60.39 (0.18-0.60)64.90.47 (0.28-0.67)0.59
    Ages 13-195851.70.38 (0.21-0.57)53.40.36 (0.16-0.57)0.86
    Ages 20-395735.10.14 (0.00-0.31)47.40.33 (0.17-0.49)0.12
    Ages 40-645846.60.34 (0.18-0.51)43.10.39 (0.22-0.55)0.75
    Ages 65+1833.30.39 (0.12-0.66)27.80.23 (0.00-0.59)0.61
Weekend days
    Ages 0-125463.00.34 (0.12-0.55)59.30.27 (0.07-0.47)0.64
    Ages 13-195669.60.56 (0.39-0.73)60.70.34 (0.13-0.55)0.08
    Ages 20-395662.50.49 (0.30-0.67)53.60.37 (0.17-0.57)0.35
    Ages 40-645554.50.45 (0.26-0.63)54.50.46 (0.28-0.64)0.90
    Ages 65+1844.40.38 (0.07-0.70)38.90.22 (0.00-0.58)0.58
  • * P value from two-sided t test comparing the difference of two weighted κ values from each questionnaire approach, with the variance of the difference estimates by the jackknife method. P value could not be calculated for the comparison of weekday sun exposure during age 65+ among females because the participants' responses were limited to two categories, whereas estimation of weighted κ values requires at least three response categories.

  • Analysis restricted to participants who answered both the test and retest questionnaires in both types of questionnaire approaches (time-based and activity-based).