Background: Speech and language therapists (SLTs) working with adults who have multiple learning disabilities and complex communication needs often deliver their care via indirect therapy where SLTs train carers to communicate with their clients. Yet, very little is known about how SLTs assess the carers' communication skills prior to the training even though the assessment should be the basis of this indirect therapy. Aims: To explore the level of agreement between Finnish SLTs' assessments of carers as skilful communication partners for adults who have multiple learning disabilities and complex communication needs. To investigate which interaction strategies affect the SLTs' assessments. Methods & Procedures: Six SLTs with more than 15 years of experience in working with individuals with complex communication needs saw together ten video clips of interaction situations between a carer and an adult who had multiple learning disabilities (aged 17-50 years). The SLTs assessed the carers on a scale from one to ten. The SLTs discussed their selections before giving their final ratings. The data were analysed both quantitatively and qualitatively. The unanimity of SLTs' assessment was analysed with a test of Kendall's "W". Furthermore, the frequencies of the carers' different communication acts were counted and these counts were compared with the mean of the carers' assessments. These results were further explored with the SLTs' justifications about their assessments. Outcomes & Results: SLTs did not fully agree on which of the carers were the most skilful interaction partners. Furthermore, the six SLTs were not unanimous about which carers' interaction strategies resulted in skilful communication. However, SLTs assessed those carers higher who used facilitative verbal acts. The carers used these verbal acts to involve themselves in the interests of the client. Conclusions & Implications: This case study showed that Finnish SLTs seem to have different criteria about what is considered skilful communication between carers and clients who have multiple learning disabilities. Even though there might not be a single way of being a skilful interaction partner, this variable can be confusing to carers if they work with several SLTs and each of them offers different professional advice. Therefore, the results suggest a need for an assessment tool for evaluating the carers' interaction skills. In addition to this tool, it appears that SLTs also need further training to be able to perform this multifaceted task. (Contains 6 tables.)