There wouldn't be 100 trainees at
Freshfields wanting to qualify into IA - the firm wouldn't recruit that way.
Plus trainees would most likely have had to sit in an IA seat/secondment to be in with a realistic chance to qualify there. That could easily mean its limited to less than 12 trainees (not sure how many IA seats they have these days) being considered for one role. And the benefit of
Freshfields is they have two qualification rounds per year, so it would never be 100 trainees - more like 40-45 qualifying at one time.
The issue with a smaller trainee intake but with a larger practice area is that 1) they tend to only have one qualification round per year where they only have one intake, and the ratios can spike much more easily than at a firm like
Freshfields. If every trainee at Debevoise rotated into IA, they could all be interested in qualifying there and all have the right experience to do so. That would not happen at a firm like
Freshfields.
But even if we said there were 12 viable trainees at
Freshfields and 10 at Debevoise to go into an IA NQ role, all it could take is for none of those to be interested, for some to be hired elsewhere and who you have actually got vying for the roles could be very different.
The key data we aren't really considering though is how many seats there are and how many NQ roles there are. That is likely to influence qualification chances than anything else. Graduate Recruitment/HR try to make this manageable - they would try to stop departments taking on 5 trainees per rotation if they had no NQ hiring plans, but ultimately sometime business demand (e.g. one big high-profile case) could lead to additional trainees being taken on for one rotation but with the view that it is unlikely going to lead to a NQ opportunity at the end of the TC. Plans also change - whether its partners leaving, unexpected paternity/maternity/sabbatical leaves, significant increases/decreases in client work, NQ hiring numbers fluctuate a lot and often unexpectedly.
This is why there is a lot of luck in the process - there are too many variables for anyone to plan or control this.