Assessment of demographic and perinatal predictors of non-response and impact of non-response on measures of association in a population-based case control study: findings from the Georgia Study to Explore Early Development

Table 1 Status of children in GA SEED^a from invitation to enrollment

Presumptive study classification at time of invitation^b	ASD	DD	POP
No. invited	274	1968	2608
Final status of invited
No. unable to contact—but indication that contact info may not have been valid (mailing returned to sender; phone number not found, disconnected, or invalid; phone call reveals phone number does not belong to desired participant)	92	696	1310
No. unable to contact—no response to mailing or follow-up phone calls and no indication that contact information was invalid	24	179	278
No. contacted, but child had aged out of study by time contact was made, eligibility screen not administered	3	241	170
No. contacted, but refused eligibility screen	46	334	358
No. contacted, but determined ineligible	18	146	266
No. contacted, eligible, but refused participation after eligibility screen	0	55	0
No. contacted, eligible and enrolled	91	317	226
Among those contacted, eligible and enrolled
No. with positive ASD screen—and thus moved to presumptive ASD protocol workflow^c	N/A^d	139	9
Final no. in each presumptive workflow	239	178	217

^aChildren born in multiple births or missing data for birth certificate analyses not included in table because they were excluded from this analysis
^bChildren from school and health sources were identified as potential ASD if they had a previous diagnosis of ASD or special education classification of autism; they were identified as potential DD if they had a previous diagnosis or special education classification indicating a non-ASD developmental disability or delay. Potential POP children were randomly sampled from birth certificates
^cAt enrollment parents of children in all groups were administered a brief ASD screen; 148 children originally identified as potential DD or potential POP had a positive score on the screen and were moved into a study work flow designated presumptive ASD. This group received a more intensive developmental assessment than other children, including administration of two autism-specific instruments
^dAll children identified as having a previous diagnosis of ASD remained in the presumptive ASD group (which received the full autism-specific developmental assessment) regardless of their autism screen results obtained at enrollment

ISSN: 1742-7622