Table 2: Durbin-Watson statistic and regression parameter estimates after correction for autoregression where appropriate
Test; specialtyDurbin-Watson statisticEstimate (95% CI)
Time (overall secular trend)Effect of interventionPostintervention slope
Lumbar spine radiography
    Family physician2.204-0.006
(-0.0119 to 0.0001)		-0.813
(-0.9883 to 0.6377)		0.0096
(0.0036 to 0.0157)
    Specialist2.522-0.0019
(-0.0043 to 0.0005)		-0.003
(-0.0757 to 0.0697)		0.0011
(-0.0018 to 0.0039)
Limited spine MRI
    Family physician2.2310.0067
(0.0051 to 0.0083)		-0.175
(-0.2221 to -0.1279)		0.0034
(0.0018 to 0.0051)
    Specialist2.2940.0009
(-0.0011 to 0.0029)		-0.102
(-0.1603 to 0.0437)		0.0022
(0.0004 to 0.0041)
Spine CT
    Family physician1.584-0.0028
(-0.0039 to -0.0017)		-0.099
(-0.1230 to -0.0750)		0.0001
(-0.0012 to 0.0014)
    Specialist2.091-0.0012
(-0.0019 to 0.0005)		-0.010
(-0.0316 to 0.0116)		0.0014
(0.0001 to 0.0028)

Note: CI = confidence interval, CT = computed tomography, MRI = magnetic resonance imaging.