The new estimate released Wednesday by the Centers for Disease Control and Prevention would mean at least one million children have autism.
The number is important - federal officials look at how common each illness or disorder is when weighing how to spend limited public-health funds.
It's also controversial.
The new statistic comes from a national phone survey of more than 95,000 parents in 2011 and 2012. Less than a quarter of the parents contacted agreed to answer questions, and it's likely that those with autistic children were more interested than other parents in participating in a survey on children's health, CDC officials said.
Still, CDC officials believe the survey provides a valid snapshot of how many families are affected by autism, said Stephen Blumberg, the CDC report's lead author.
The study that came up with the 1-in-88 estimate had its own limitations. It focused on 14 states, only on children 8 years old, and the data came from 2008. New figures based on medical and school records are due next year.
There are no blood or biologic tests for autism, so diagnosis is not an exact science. It is identified by making judgments about a child's behavior.
Doctors have been looking for autism at younger and younger ages, and experts have tended to believe most diagnoses are made in children by age 8.
But the new study found many children were diagnosed at older ages.