Table 2 Descriptive parameters of demographic, morbidity and treatment variables with design effects (Deff), intra-cluster correlation coefficients (ICC) and standard errors of ICC (SE) for sample year April 1999 to March 2000 (N = 1,047 general practitioners): compared with ICC and SE for sample April 2002 to March 2003 (N = 1,008 GPs).

59.0 (.39)

6.4

.055 (.003)

59.3

.066 (.003)

44.5 (.31)

16.6

.159 (.006)

45.4

.153 (.006)

40.1 (.70)

21.4

.206 (.007)

42.7

.209 (.008)

7.0 (.53)

45.6

.451 (.011)

8.8

.423 (.011)

149.5 (.86)

13.6

.127 (.005)

148.7

.141 (.006)

Cardiovascular (%)

15.2 (.29)

6.7

.057 (.003)

15.3

.056 (.003)

Respiratory (%)

21.0 (.26)

4.2

.032 (.002)

19.0

.040 (.002)

Psychological (%)

10.6 (.25)

6.8

.059 (.003)

10.6

.061 (.003)

Endocrine/Metabolic (%)

8.8 (.18)

4.2

.032 (.002)

10.1

.031 (.002)

Blood (%)

1.7 (.08)

3.7

.027 (.002)

1.4

.007 (.001)

Digestive (%)

9.6 (.12)

1.8

.008 (.001)

9.7

.010 (.001)

Eye (%)

2.8 (.06)

1.5

.005 (.001)

2.6

.003 (.001)

Musculoskeletal (%)

16.3 (.23)

4.1

.032 (.002)

16.5

.045 (.002)

Skin (%)

16.1 (.19)

2.7

.017 (.001)

15.9

.042 (.002)

General unspecified (%)

14.0 (.22)

4.3

.034 (.002)

15.8

.043 (.002)

Any medications

67.0 (.37)

6.6

.056 (.003)

64.4

.068 (.003)

Any referrals

11.2 (.20)

4.1

.031 (.002)

12.0

.033 (.002)

Any pathology tests ordered

14.7 (.26)

5.8

.048 (.002)

16.0

.046 (.002)

Any imaging tests ordered

6.9 (.15)

3.8

.028 (.002)

7.8

.029 (.002)