The confusion makes sense because BCG London uses different assessments depending on the role.
For Associates (undergrad/Master's): you get a short numerical test after the CV screen, then another CV review, then interviews.
For Consultants (MBA/experienced hire): you get the Casey chatbot case. It's 8 to 10 questions, takes 25 to 35 minutes, and ends with a 1-minute video recommendation. Mix of multiple choice, short answer, and some math. You can't go back once you submit an answer.
There's also a newer step called the CCA (Consulting Career Assessment), introduced in 2024. BCG sends it right after you apply. It takes about 30 minutes, most sections are untimed, and calculators are allowed. Your score decides whether you move on to the Casey chatbot.
The old Potential Test is no longer used as of 2026.
So the mixed reports you've seen are probably people on different tracks, or comparing old and new formats.