Table 4

Results of sensitivity analysis: costs, benefits, and benefit:cost ratios (BCR)

Age 5–12Age 13–18Adults
Costs of law ($)Value of benefits ($)BCRCosts of law ($)Value of benefits ($)BCRCosts of law ($)Value of benefits ($)BCR
*Base case: cost of helmet = $19.95; life of helmet = 5 years; discount rate = 5%; no quitters; head injuries averted per year: 4.0 5–12 years, 10.3 13–18 years, 28.8 adults; treatment costs: $1569 5–12 years, $1607 13–18 years, $1351 adults; societal cost of serious head injury = $196360; societal cost of minor head injury = $13309.
Base case*180792471920 2.61150731212790500.85581939742896020.74
Cost of helmet: $50.00453769471920 1.04376191212790500.341479173142896020.29
Cost of helmet: $10.0090580471920 5.2175683412790501.69291809742896021.47
Life of helmet: 7 years180792629156 3.48150731217032631.13581939757030090.98
Life of helmet: 3 years180792298307 1.6515073128139480.54581939727351170.47
Law enforcement costs287727471920 1.64176058612790500.73656406542896020.65
Discount rate: 10%180792426669 2.36150731211606300.77581939738989960.67
Discount rate: 0%180792522489 2.89150731214168730.94581939747719060.82
Head injuries averted: upper CI1807921180572 6.53150731217334091.15581939752956510.91
Head injuries averted: lower CI1807920 015073128290220.55581939733170560.57
Costs of head injury increase 20%180792565879 3.13150731215374581.02581939751792630.89
Costs of head injury decrease 20%180792377855 2.09150731210249720.68581939734334440.59
Numbers of quitters76697244574731.89670778888790813.254349481152585053.51
Cost of quitting: $19.95193803244574712.62161187988879085.516003137152585052.54
Cost of quitting: $49.953699032445747 6.61302706988879082.948489837152585051.80