Table 1 

Variable definitions and descriptive statistics. 

Mean 

Variable 
Definition 
1976 
Whole material 
2005 


caesar 
= the proportion of Caesarean sections 
0.047 
0.108 
0.146 
(0.028) 
(0.044) 
(0.049) 

rev_hosp 
= hospital revenue per bed in NOK 1000, deflated to 1970 prices 
101.32 
205.42 
364.43 
(20.25) 
(91.41) 
(66.99) 

age_le20^{1} 
= the proportion of mothers less than 20 years 
0.116 
0.057 
0.026 
(0.033) 
(0.033) 
(0.013) 

age_hi35^{1} 
= the proportion of mothers older than 35 years 
0.044 
0.072 
0.117 
(0.015) 
(0.031) 
(0.030) 

edu_univ^{2} 
= the proportion of mothers with university/college education 
0.126 
0.305 
0.450 
(0.037) 
(0.101) 
(0.107) 

edu_uss^{2} 
= the proportion of mothers with upper secondary school education 
0.557 
0.453 
0.362 
(0.056) 
(0.073) 
(0.076) 

weight_le2500^{3} 
= the proportion of babies with a birthweight less than 2500 g 
0.045 
0.034 
0.031 
(0.016) 
(0.020) 
(0.021) 

weight_hi4500^{3} 
= the proportion of babies with a birthweight greater than 4500 g 
0.031 
0.039 
0.042 
(0.011) 
(0.013) 
(0.013) 

ab_present 
= the proportion of babies with abnormal presentation (including breech 
0.043 
0.059 
0.088 
presentation, transverse presentation, abnormal cephalic presentation and other) 
(0.016) 
(0.024) 
(0.030) 

preeclam 
= the proportion of mothers with preeclampsia (including unspecified, mild and severe) 
0.021 
0.029 
0.031 
(0.111) 
(0.015) 
(0.016) 

mult_birth 
= the proportion of mothers with multiple births 
0.025 
0.024 
0.025 
(0.010) 
(0.024) 
(0.019) 

no_births 
= the number of births in total 
838 
1028 
1176 
(723) 
(1034) 
(1388) 

weekend 
= the proportion of births on a Saturday or a Sunday 
0.248 
0.248 
0.274 
(0.025) 
(0.031) 
(0.111) 

year_2002 
= 1 if year equals 2002 to 2005, 0 otherwise 



Mean values and standard deviation in brackets. ^{1 }Reference category: the proportion of mothers aged 2035 years ^{2 }Reference category: the proportion of mothers with compulsory school education ^{3 }Reference category: the proportion of babies with a birthweight 25004500 g 

Grytten et al. BMC Health Services Research 2011 11:267 doi:10.1186/1472696311267 