Effects of a reimbursement change and travel times on the delivery of private and public radiology services in Norway: a register-based longitudinal study of Norwegian claims data

Table 1 Variables and summary statistics nationally before/after the change of 1 January 2008

Variable	Explanation of variables	2007–2010		Before 2008		After 2008
Variable	Explanation of variables	Median	IQR	Median	IQR	Median	IQR
Priv_Serv	Number of services per 1000 inhabitants in the municipality done at private providers per month, services/1000 inhabitants	6.98	9.13	8.22	10.32	6.65	8.72
Pub_Serv	Number of services per 1000 inhabitants in the municipality done at public providers per month, services/1000 inhabitants	25.46	14.27	23.72	13.32	26.04	14.43
Total_Serv	Total number of services per 1000 inhabitants in the municipality per month, services/1000 inhabitants × month	33.95	12.43	33.95	12.29	33.95	12.49
Privtime	The travel time from the municipality of the patient^b to the nearest municipality with a private radiology provider in hours	1.55	2.58	1.57	2.61	1.55	2.50
Pubtime	The travel time from the municipality of the patient^b to the nearest municipality with a public radiology provider in hours	0.82	1.17	0.80	1.17	0.82	1.17
Time_difference	Privtime-Pubtime in hours	0.50	1.72	0.50	1.70	0.50	1.72

	Dummy variables	Mean	Mean	Mean
Centrality0	Dummy for least central municipalities: Centrality 0A and 0B^a, population less than 1000	0.33	0.34	0.33
Centrality1	Dummy for Centrality 1A and 1B^a, population from 1000 to 15,000	0.33	0.32	0.33
Centrality2	Dummy for Centrality 2A and 2B^a, population from 15,000 to 50,000	0.26	0.26	0.26
Centrality3	Dummy for most central municipalities: Centrality 3^a, population from 50,000	0.08	0.08	0.08
Region1	Dummy for the Regional Health Authority South East	0.41	0.40	0.41
Region2	Dummy for the Regional Health Authority West	0.20	0.20	0.20
Region3	Dummy for the Regional Health Authority Central	0.19	0.19	0.19
Region4	Dummy for the Regional Health Authority North	0.20	0.20	0.20
N n		19,867 422	4944 415 ^c	14,923 422 ^c

“Before 2008”, the data covers 2007, or 12 periods; “After 2008”, the data covers 2008–2010, or 36 periods; IQR, interquartile range; N, number of observations; n, number of municipalities
^aCentralities classified by Statistics Norway
^bMunicipality of the GP of the patient was used as a proxy of the municipality of the patient, as patients usually choose a GP in the same municipality, except in municipalities that are so small that the nearest GP is in another nearest municipality
^cThe difference in the number of municipalities in the data is due to structure of claims data. The total number of municipalities is 422

ISSN: 1478-7547