Table 6

Adjusted associations between participation in the extended hours access scheme and patient experience, using multilevel random-effects regression models, propensity score matching and instrumental variable analysis

Satisfaction with opening hoursExperience of making an appointmentOverall experience
Number of responses731 700725 885753 020
Number of general practices739973997399
Between-practice SD*
Random-effects regression models
 Mean difference (95% CI)1.25 (0.96 to 1.55)0.48 (0.07 to 0.90)0.32 (0.04 to 0.60)
 p Value<0.0010.0220.026
 Standardised mean difference0.280.070.07
Propensity score matching
 Mean difference (95% CI)1.35 (1.00 to 1.70)0.51 (−0.03 to 1.04)0.39 (0.03 to 0.74)
 p Value<0.0010.0630.032
 Standardised mean difference0.300.070.09
Instrumental variable analysis
 Mean difference (95% CI)1.36 (0.71 to 2.00)1.79 (0.84 to 2.75)1.13 (0.50 to 1.76)
 p Value<0.001<0.001<0.001
 Standardised mean difference0.300.250.26
  • Numbers of responses and general practices correspond to respondents with no missing data for relevant outcome models.

  • Mean differences are relative to the means for general practices not participating in the scheme.

  • All models adjusted for/balanced: respondent age, gender, ethnicity, socio-economic status, ability to take time off work to see a GP, confidence in managing health; and general practice registered population size, number of full-time-equivalent GPs per 10 000 patients, socio-economic status of registered population, Quality and Outcomes Framework achievement, urban/rural location and region of England.

  • *SD of practice-level random effects adjusted for patient characteristics only. Standardised mean differences equal mean differences divided by this SD.