One potential issue is that ASD= 20-30 hours per week of specific, generally effective services, whereas everything else = good luck finding anything that will help you. Parents know this- particularly for younger kiddos where they have been primed by EI or other such therapists. In essence, you are delivering "bad", if not confusing or ambiguous news. I almost always find it more difficult to not diagnose ASD.
In my feedback, I go over every area of development (maybe not physical, if there are no concerns), giving specific feedback and examples (including reviewing formal test results) regarding language, cognitive, social initiation, social responsiveness, play, and repetitive behaviors or interests. I then tie these things directly into why I did or did not offer an ASD diagnosis (or did offer another diagnosis, which is usually something like global delay, language delay, or social pragmatic communication disorder). I then- before getting into recommendations- ask if they feel I've accurately described their child. If not, we try to figure out where the discrepancy lies and come up with a plan for closing that gap (such as additional testing, come back in 3 or 6 months, etc. I also am not too proud to give a general sense of how certain I am about not making a diagnosis (for example, I may say that I like to be 95% sure that it's not ASD, but in this case I'm only 75% sure). If I'm less than 90% sure, there WILL be a plan for further check-in/assessment after 3-6 months of continued services WITH the addition of anything I recommend.
I also feel that, if a parent has brought their kiddo to me, there is something not going right and something needs to change. Coming up with a diagnostic label is secondary to identifying needed services. That's often a referral to speech therapy (or more intensive speech therapy), recommendations for SPECIFIC and empirically validated social skills instruction, or accessing any behavioral/mental health services that might be needed. There is always a specific action plan with objective and measurable steps that I can evaluate when I see the kiddo again. Even if it's something as simple as "call the insurance company for a list of providers, and then contact me if you have any difficulties finding appropriate services"- having a specific plan can temper some of the confusion and uncertainty.
