Table 3 Table of assignments of variables

Case control

0 = Control

1 = Case

the relationship between caretaker and children

0 = Father/mother

1 = Grandparent

Education level of primary caregivers

1 = Elementary school and below

2 = Junior high school

3 = High school and above

Smoking status of primary caregivers

1 = Often

2 = Occasionally

3 = Never

Drinking situation of primary caregivers

1 = Often

2 = Occasionally

3 = Never

physical condition of primary caregivers

0 = Health

1 = Sick

Are there other children in the family?

0 = No 1 = Yes

Is it a left-behind child?

0 = No 1 = Yes

Total annual income of the family

1 = < 20,000 2 = 20,000~79,999 3 = ≥80,000

Is there a water storage container in the house?

0 = No 1 = Yes

Whether the container holds water

1 = Often

2 = Occasionally

3 = Never

Whether the container has a lid or fence

0 = No 1 = Yes

Is there a water body near the place of residence?

0 = No 1 = Yes

Whether the water body has a lid or fence

0 = No 1 = Yes

Is there a medical institution within 500 m of the current residence?

0 = No 1 = Yes

Does the child have full-time care?

0 = No 1 = Yes

Father’s time spent with children in the last month

1 = <7 h 2 = 7~20 h

3 = 21~34 h 4 = ≥35 h

Mother’s time spent with children in the last month

1 = <7 h 2 = 7~20 h

3 = 21~34 h 4 = ≥35 h

The most common way to take a bath for children in the past month

0 = bathtub

1 = take a shower

Caregiver swimming ability

1 = can not swim

2 = not very skilled

3 = skilled

Caregivers think that children should be taught to swim

0 = No 1 = Yes

Has the caregiver taught children to swim?

0 = No 1 = Yes

Have children ever swum or played by the water in the past 6 months?

1 = Often

2 = Occasionally

3 = Never

Whether the caregiver has the emergency rescue knowledge of drowning

0 = No 1 = Yes

Has the child(≥1 year) received safety education for unintentional drowning?

0 = No 1 = Yes