Multiple BCBA supervisors is preferred whenever possible. The more exposure you can get to unique approaches to ABA, the better you will be when you become a BCBA. Here are some things to keep in mind when you are exploring multiple supervisors.
Your documentation and experience requirements changed based on if your supervisors are in the same organization or multiple organizations. If you only work 1 job and your supervisors work for the same company (most common) then you can consider your supervisions as multiple supervisors in the same organization. If you have supervisors that work for different companies then you would consider your supervisors to be from different organizations.
Now that you know how to distinguish between the two, let's talk about the impact on your documentation and experience requirements.
This is the easiest way to have multiple supervisors. You are able to share your encounters and observations across your supervisors. So if you need 4 encounters per month, you may have 3 with Supervisor A and 1 with Supervisor B. You may meet with each of them and either can sign off on your monthly and final hours. You will need to use the multiple supervisors Monthly Experience Verification Form.
However, make sure your supervision contract clearly states that you may be supervised by multiple people. Ideally you will have each supervisor named in the supervision contract. If you cannot do that, or a supervisor is added after the supervision contract is executed, then you should at least pursue an addendum to the contract. Have something in writing signed by you and the supervisor that states the additional supervisor is involved in your supervision experience.
If each supervisor belongs to a different organization, then you must meet all encounter and observation requirements for each supervisor. So if you need 4 encounters per month, you would need to meet 4 times with Supervisor A and 4 times with Supervisor B. The amount of hours you need to be supervised does not double, but the amount of encounters, observations, Monthly Experience Verification Forms, and Final Experience Verification Forms you need do double. Make sure you use the Individual Supervisor Monthly Experience Verification Form for each supervisor that you meet with.
This may sound like a lot of work, but practically it is just more documentation. You are still meeting with your supervisors for the same amount of total time, but you will likely meet more frequently for shorter periods of time so you can get all of your encounters in for each supervisor.
If there is only 1 BCBA at your work or you want an outside perspective, you may choose to find a second supervisor. One option is to reach out to supervisors in your area through the BACB registry. However, the best way to find a second supervisor is to search online for "remote BCBA supervision". You will find a handful of companies that provide remote supervision, including our company (Hoom House). Please consider us for your supervision needs.
Hopefully this helps clear up some of the confusion around having multiple BCBA supervisors during your fieldwork supervision experience. Standards and requirements change from time-to-time so always defer to the BACB and your state/local governing bodies for the latest changes.