Background: Prospective foster carers undergo an assessment of their suitability. The two most common assessment methods in Sweden are the Original Kälvesten (OK) and the New Kälvesten (NK). None of them have been empirically tested. The present study offers the first scholarly insights into the NK method.Methods: We were graciously allowed access from the founders to documentation of the method, including complete educational materials aimed at social workers (e. g., >8 hours recorded lectures). These materials were analysed qualitatively in a data-driven fashion with the purpose of describing and reviewing the NK method. Two semi-structured interviews were conducted with founders and educators to supplement the materials. In addition, 268 websites of licensed Swedish agencies conducting assessments of prospective foster carers were screened for mentioning of which interview method they use.Results: The interview protocol primarily aimed at measuring attachment style (38%) and attachment and affects (17%); 10% was claimed to measure affects; 10% mentalisation; 24% were not connected to any outcome measure. We found that NK, just like the OK interview, prohibits recording of the interviews. Instead were interviewers instructed to transcribe interviews verbatim in real time. The transcript was read back to the analyst in a role play fashion during which the analyst conducted a quick linguistic analysis resulting in a binary yes/no decision on suitability. Of 268 agencies, 114 named an interview method: 51% reported use of NK; 44% Kälvesten; 4% Casey Home Assessment Protocol – Fostering Challenges. Conclusions: The NK method was found to be unethical in at least six ways: applicants were exposed to deliberate stress evocation; they were rejected when risk factors occurred without considering protective factors; they were not provided adequate feedback; interview outcome was unsuitable for linguistic analysis; high risk of interviewer and analyst biases; the method can be described as pseudoscientific. Recommendations for future research and practice are made.