The residual plots for Associate dentists appear to support the first three assumptions for multiple linear regression of the average ‘motivation index’ as does the almost linear quantile plot.
Different Dental Populations
Table F2 shows the parameter estimate results listed in table 1.8 (Chapter 1) together with the pvalue for each and the adjusted Rsquared results.
Table F2: Parameter estimates and pvalues for ‘motivation index’ by dental type and split populations using multiple linear regression, England, 2019/20
Dental Type 
Population 
Sample 

Parameter Estimate 
Intercept 
Weekly Hours 
NHS% 
Clinical% 
Leave 
Age 
Adjusted R^{2} 
ProvidingPerformer 
All 
1,059 

Estimate 
64.092 
0.183 
0.232 
0.074 
0.964 
0.010 
0.155 



Pvalue 
<.0001 
0.001 
<.0001 
0.060 
0.007 
0.890 

<35 Hours 
229 

Estimate 
53.070 
0.195 
0.163 
0.014 
1.129 
0.031 
0.092 



Pvalue 
<.0001 
0.330 
<.0001 
0.827 
0.084 
0.837 

≥35 Hours 
830 

Estimate 
71.710 
0.331 
0.252 
0.073 
1.098 
0.004 
0.171 



Pvalue 
<.0001 
<.0001 
<.0001 
0.143 
0.011 
0.960 

Mainly NHS 
552 

Estimate 
94.117 
0.314 
0.472 
0.030 
0.712 
0.025 
0.062 



Pvalue 
<.0001 
<.0001 
<.0001 
0.612 
0.197 
0.815 

Mainly Private 
240 

Estimate 
65.084 
0.106 
0.414 
0.132 
1.058 
0.299 
0.040 



Pvalue 
<.0001 
0.337 
0.020 
0.046 
0.079 
0.058 

Male 
764 

Estimate 
54.243 
0.211 
0.241 
0.124 
0.986 
0.108 
0.180 



Pvalue 
<.0001 
0.002 
<.0001 
0.011 
0.017 
0.216 

Female 
295 

Estimate 
76.329 
0.006 
0.236 
0.014 
0.571 
0.186 
0.115 




Pvalue 
<.0001 
0.953 
<.0001 
0.829 
0.414 
0.164 

Associate 
All 
2,437 

Estimate 
66.366 
0.095 
0.204 
0.079 
0.472 
0.137 
0.078 



Pvalue 
<.0001 
0.023 
<.0001 
0.010 
0.012 
0.000 

<35 Hours 
1,065 

Estimate 
62.668 
0.012 
0.170 
0.006 
0.757 
0.074 
0.064 



Pvalue 
<.0001 
0.896 
<.0001 
0.891 
0.010 
0.207 

≥35 Hours 
1,372 

Estimate 
76.397 
0.308 
0.244 
0.126 
0.251 
0.157 
0.097 



Pvalue 
<.0001 
0.001 
<.0001 
0.003 
0.306 
0.003 

Mainly NHS 
1,700 

Estimate 
74.233 
0.142 
0.282 
0.070 
0.576 
0.110 
0.022 



Pvalue 
<.0001 
0.006 
<.0001 
0.059 
0.007 
0.022 

Mainly Private 
285 

Estimate 
62.358 
0.149 
0.518 
0.131 
0.050 
0.191 
0.041 



Pvalue 
<.0001 
0.200 
0.002 
0.127 
0.941 
0.096 

Male 
1,110 

Estimate 
60.355 
0.144 
0.214 
0.151 
0.209 
0.079 
0.093 



Pvalue 
<.0001 
0.024 
<.0001 
0.002 
0.461 
0.161 

Female 
1,327 

Estimate 
68.601 
0.029 
0.204 
0.022 
0.692 
0.172 
0.071 




Pvalue 
<.0001 
0.628 
<.0001 
0.571 
0.006 
0.003 

Northern Ireland
Table F3 shows the parameter estimate results listed in table 2.7 (Northern Ireland – 2019/20, Multivariate Analysis) of the main report together with the pvalue for each and the adjusted Rsquared results. The intercept represents value of the ‘motivation index’ when all explanatory variables are zero.
Table F3: Parameter estimates and pvalues for ‘motivation index’ by dental type using multiple linear regression, Northern Ireland, 2019/20
Dental Type 
Sample 

Parameter Estimate 
Intercept 
Weekly Hours 
NHS% 
Clinical% 
Leave 
Age 
Adjusted R^{2} 
Principal 
138 

Estimate 
64.148 
0.067 
0.279 
0.080 
2.440 
0.004 
0.195 


Pvalue 
0.000 
0.623 
<.0001 
0.525 
0.019 
0.982 

Associate 
200 

Estimate 
101.366 
0.101 
0.372 
0.049 
0.068 
0.970 
0.190 


Pvalue 
<.0001 
0.567 
<.0001 
0.694 
0.956 
<.0001 

Based on the results it is possible to predict the ‘motivation index’ for dentists. For example, for Principal dentists in Northern Ireland this is given as:
64.148  (0.067 x WH)  (0.279 x NHS%)  (0.080 x Clinical%) + (2.440 x Leave) + (0.004 x Age)
As described in Annex E, residual plots for Principal dentists in Northern Ireland are shown in figure F5.
Figure F5: Principal dentists, plot of residuals for average ‘motivation index’ versus individual independent variables, Northern Ireland, 2019/20