5 why's refers (afaik) to the depth of the why tree. If the first why has 3 answers, then you ask why 3 more times to each answer (n = 4, depth = 2) If each of

5 why's refers (afaik) to the depth of the why tree. If the first why has 3 answers, then you ask why 3 more times to each answer (n = 4, depth = 2) If each of those 3 whys have 2 answers, you would ask why 6 more times (n=10, depth = 3) If each of those whys have 3 answers, we would need to ask why a further 18 times! (N=28, depth = 4) That is leaving out the last depth, but suffice to say there are a lot more than just 5 questions. It seems rare for any system where the cause and effect tree is linear. Hence, 5 whys is meant to be very holistic, not just deep.