Skip to main content


Table 3 Tobit regression model to show predictors of WTP for most preferred intervention

From: Comparing how patients value and respond to information on risk given in three different forms during dental check-ups: the PREFER randomised controlled trial

 CoefficientStandard errortp > tLower 95% CIUpper 95% CI
Intervention most preferredVerbalReference
Traffic light9.653.812.530.0122.1517.15
Deprivation (IMD decile)8–10 (high)−7.143.10−2.310.022−13.24−1.04
4–7 (medium)Reference
1–3 (low)−4.172.80−1.490.138−9.691.35
Income per annum£31,200+−2.402.90−0.830.409−8.113.32
EducationUniversity degree (high)0.053.300.010.988−6.466.56
A-levels (medium)Reference
GCSE or less (low)−2.989.48
Age18–34 years−.753.04−0.250.806−6.735.24
34–64 yearsReference
65+ years−3.633.35−1.080.280−10.232.98
Number of teeth< 20 teeth6.943.511.980.0490.03213.85
20+ teethReference
Dental attendanceInfrequent (< 6 times in 5 years)−0.453.02−0.150.881−6.415.50
Normal attender (6+ in 5 years)Reference
LiteracyLow REALM-R−11.035.09−2.170.031−21.05−1.00
Normal/high REALM-RReference
PracticePractice 13.203.510.910.363−3.7210.11
Practice 210.143.412.970.0033.4216.85
Practice 32.763.800.730.468−4.7210.24
Practice 4Reference
  1. n = 254, Likelihood Ratio of χ2 = 32.52 (p = 0.0129), pseudo-R2 = 0.017
  2. CI confidence interval, IMD Index of Multiple Deprivation, REALM-R Rapid Estimate of Adult Literacy in Medicine, Revised, WTP willingness to pay