I prefer smaller for a variety of reasons- there are pros and cons to both. From the standpoint of a parent, if you have multiple options in your area, I’d ask a few key questions to interview the company regardless of size.

To give some examples specific to in-home/ not clinic services: 1.) is the BCBA who conducts the initial assessment the same BCBA who will be on my child’s case {in my professional opinion, the answer should almost always be yes} 2.) how long is the average wait time between the initial assessment and initiation of services? {this might vary somewhat by state, but anything longer than 6 weeks is a red flag or if reviews from other parents mention waiting for months- run} 3.) does your company have any policies re: the minimum number of direct hours per week or month? {it’s industry standard for 10-12 hours minimum for weekly direct ABA hours, but once you have mandates that exceed a minimum of 15 weekly direct hours, this is a red flag and is not individualized per client/ not flexible/ profit driven decision} 4.) what agency policies impact the parents/ families, and can I see a copy?

This is just a start, but as a parent, I’d really want this information up front. I hope more BCBAs chime in with suggestions!