Definitions of the dependent and independent variables.
Variable
Dependent variables
Probability
Traffic accident with head injury = 1; other = 0
Medical cost
NT dollarsa
Length of stay in hospital
Inpatient days
Independent variables
Policy
After motorcycle helmet use law = 1;
Before motorcycle helmet use law = 0
Geographic location
North
Patient lived in Taipei City, Keelung City, Taipei County, Yilan County, Hsinchu City, Taoyuan County, Hsinchu County, and Miaoli County; yes = 1, other =0
Center
Patient lived in: Taichung City, Taichung County, Changhua County, and Nantou County; yes = 1, other = 0
South
Patient lived in: Tainan City, Chiayi City, Yunlin County, Chiayi County, Tainan County, Kaohsiung City, Kaohsiung County, Pingtung County, and Penghu County; yes = 1, other = 0
East
Patient lived in: Hualien County and Taitung County; yes, other =0
Gender
Male = 1; female = 0
Age
Children
Patient’s age from 0 to 14 years old = 1; other = 0
Adult 15–24
Patient’s age from 15 to 24 years old = 1; other = 0
Adult 25–64
Patient’s age from 25 to 64 years old = 1; other = 0
Elderly
Patient’s age over 65 years old = 1; other = 0
Rural/urban
b
Special municipality
Patient lived in special municipality (regions with populations of not less than 1,250,000 and have special requirements in their political, economic, cultural, and metropolitan developments) = 1; other = 0
City
Patient lived in city (regions with populations of not less than 500,000 but not more than 1,250,000 and occupy major political, economic, and cultural roles) = 1; other = 0
County administered
Patient lived in county-administered (regions with populations of not less than 150,000 but not more than 500,000, and possess thriving industrial and commercial development, adequate financial resources for self-government, convenient transportation, and comprehensive public facilities) = 1; other = 0
Town
Patient lived in town (regions with populations of less than 150,000, and possess thriving industrial and commercial development) = 1; other = 0
Village
Patient lived in village (regions with populations of less than 150,000, and less economic development) = 1; other = 0
aUS$1 = NT$33.4 in 1998.
bRural/urban stratify according to the Local Government Act.