Table 1.

Definitions and values of variables

	Definitions and values
Occurrence of drowning (y)*	No = 0, Yes = 1
Age (Years)(X1)	8≦X1 < 10 = 0, 10≦X1 < 12 = 1, 12≦X1 < 14 = 2, 14≦X1 < 18 = 3
Gender (X2)	Males = 0, Females = 1
Swimming skill (Meters) (X3)	≧100 = 0, 50–100 = 1, < 50 = 2, Unable to swim =3
Personality (X4)	Introvert = 0, Extrovert = 1, Between introvert and extrovert = 2, Do not know = 3
Relationships with classmates (X5)	Very good = 0, Good = 1, Not good = 2, Bad = 3
Relationships with family (X6)	Very good = 0, Good = 1, Not good = 2, Bad = 3
Number of siblings (X7)	One = 0, two or over = 1
Distance from school to open water (Meters) (X8)	< 100 = 0, 100–500 = 1, 500 + =2, None = 3, Do not know = 4
Distance from home to open water (Meters) (X9)	< 100 = 0, 100–500 = 1, 500 + =2, None = 3, Do not know = 4
Have open water on the way to school (X10)	Yes = 0, No = 1, Do not know = 2

*Occurrence of drowning: once had the experience of drowning = Yes; had no experience of drowning = No