Table 1 Modified Newcastle Ottawa Scale

   Case definition

Yes, with independent validation

2

Yes, record linkage/self report

1

No description

0

   Representativeness

Consecutive cases

1

Potential for selection bias/not stated

0

   Selection of controls

Community

2

Hospital/clinic/school

1

Potential for selection bias/not stated

0

   Definition of controls

No family history of autism spectrum disorder

2

Healthy/other psych/developmental/genetic

1

disorder

Poorly defined/not stated

0

2. Comparability of cases and controls on the basis of the design

   Study controls for age

1

   Study controls for gender

1

3. Exposure

   Ascertainment of exposure

Laboratory blinded to case/control status

1

Laboratory unblinded/not stated

0

   Method of ascertainment same for cases and controls

Yes

1

No

2

4. Additional criteria for genetic studies

a. Consideration of Hardy Weinberg Equilibrium

Yes

1

No

0

b. Power calculations

Yes

1

No

0

c. Correction for multiple comparisons

Yes

1

No

0

d. Adjustment for population stratification

Yes

1

No

0