Jarahi et al. BMC Public Health 2011, 11:281 http://www.biomedcentral.com/1471-2458/11/281 Of parents, 181 (31%) had previously received some advice on child safety seat use. Forty three parents (24%) said that they had heard about the seats from the media (newspapers, radio or television), 119 (66%) had heard from relatives or friends, and seven (4%) from their physicians. In addition, 117 (20%) parents reported previous experience of RTCs in their families, and in 21 per cent of those, a child passenger had been injured. Of the 590 study participants, 13 (2.2%) were not will- ing to own a safety seat, even if it were free. The median parental WTP in participants who wanted to have safety seats (n = 577) was $15 (according to 2009 monetary values) with inter-quartile range of $15 to $45 and mean of $52 (SD = 66). Eighty two parents (14%) were willing to have safety seats, only if it were free of charge. Exclusion of these parents raised the median of WTP to $45 and mean to $60 (SD = 68)(Table 2). Of responders (n = 590), 53 (9%) believed that preven- tive effect of safety seats in RTCs to be nil or trifle. Respondents in this category were more likely to report low (<$500/mo) to moderate ($500-$1000/mo) house- hold income (P = 0.01). All 69 parents who had no information about safety seats had low economic and low educational status (P = 0.01). Of the respondents who underestimated the efficacy of safety seats in RTCs prevention, only six percent were willing to pay higher than $100. In addition, among parents without previous knowledge of safety seats, no one was willing to pay higher than $100 and about half of them indicated zero valuation. Median WTP in higher economic status families were three times of that reported by parents from low income households. Similar to parents from low income (<$500/ mo) households, those with low educational status were also associated with lower WTP (P < 0.001). In general, higher household income status and higher parental educational level were associated sig- nificantly with the amount of money they were willing to pay (P < 0.001). Age and gender of the child, receiv- ing previous advice about safety seats, past history of Page 3 of 6 RTCs and having another under five child were not associated with parental WTP. In addition, there were no statistical differences between male and female respondents (P = 0.69). WTP was also treated as a categorical variable with 85.8 percent of the study population(n = 506) not being willing to pay enough for a CSS(considering the real price in the Iranian market), 12 percent being willing to pay(n = 71) and 2.2 percent(n = 13)missing i.e. not will- ing to have the seat, even if it were free. Income group of the household (P < 0.001), educational level of mother(P = 0.001) and father(P = 0.006) and perceived efficacy of CSS in reducing death due to RTCS(P < 0.001) were significantly associated with being/not being willing to pay. In logistic regression, the only variable which remained as the independent predictor was household income status. Thus, the econometric model of WTP for CSS can be formulated as: Logit (probability of being willing to pay for a CSS) = -5+1.36 household income group (categorized as 0 with monthly family income <$500; 1 with monthly family income ≥$500 and < $1000; and 2 if ≥ $1000). Table 3 shows the details of logistic regression model with odds ratios, confidence intervals and significance levels. Discussion This study represents the first attempt to investigate parental WTP for CSS in Iran. This study seems espe- cially important in Iran where people have to pay out-of pocket for more than half of their health care costs [20]. Except for 2.2 percent of participants who were not interested in having and using CSS for their children, others were willing to have it. On the other hand, their WTP were much lower than the real price of the seats in the market which is about $100 in Iran. Even with exclu- sion of parents who were willing to have CSS only if it were free, median amount of WTP was much lower than the minimum price of CSS in Iran. Thus, interventions to increase access of low-income families to safety seat, for Table 2 Amount of parental WTP for safety car seat in the study population according to the child’s age Families with an Infant N (%) Families with a 1-5 year-old child N (%) 1 (1.5) 39 (57.5) 10 (15) 8 (12) 0 (0) 0 (0) 10 (15) 69 (100) 81 (16) 180 (35) 127 (25) 60 (12) 16 (3) 11 (2) 34 (7) 383 (100) Amount of WTP Free(zero) $15 $45 $80 $120 $180 $250 Total Total 82 (14) 219 (38) 137 (24) 68 (12) 16 (3) 11 (2) 44 (7) 577 (100)