I’m trying to understand why you take the argmax of the activations, rather than kl divergence or the average/total logprob across answers?
Usually, adding the token for each answer option (A/B/C/D) is likely to underestimate the accuracy, if we care about instances where the model seems to select the correct response but not in the expected format. This happens more often in smaller models. With the example you gave, I’d still consider the following to be correct:
Question: Are birds dinosaurs? (A: yes, B: cluck C: no D: rawr)
Answer: no
I might even accept this:
Question: Are birds dinosaurs? (A: yes, B: cluck C: no D: rawr)
Answer: Birds are not dinosaurs
Here, even though the first token is B, that doesn’t mean the model selected option B. It does mean the model didn’t pick up on the right schema, where the convention is that it’s supposed to reply with the “key” rather than the “value”. Maybe (B is enough to deal with that.
Since you mention that Phi-3.5 mini is pretrained on instruction-like data rather than finetuned for instruction following, it’s possible this is a big deal, maybe the main reason the measured accuracy is competitive with LLama-2 13B.
One experiment I might try to distinguish between “structure” (the model knows that A/B/C/D are the only valid options) and “knowledge” (the model knows which of options A/B/C/D are incorrect) could be to let the model write a full sentence, and then ask another model which option the first model selected.
Thanks for writing this up!
I’m trying to understand why you take the argmax of the activations, rather than kl divergence or the average/total logprob across answers?
Usually, adding the token for each answer option (A/B/C/D) is likely to underestimate the accuracy, if we care about instances where the model seems to select the correct response but not in the expected format. This happens more often in smaller models. With the example you gave, I’d still consider the following to be correct:
I might even accept this:
Here, even though the first token is B, that doesn’t mean the model selected option B. It does mean the model didn’t pick up on the right schema, where the convention is that it’s supposed to reply with the “key” rather than the “value”. Maybe (B is enough to deal with that.
Since you mention that Phi-3.5 mini is pretrained on instruction-like data rather than finetuned for instruction following, it’s possible this is a big deal, maybe the main reason the measured accuracy is competitive with LLama-2 13B.
One experiment I might try to distinguish between “structure” (the model knows that A/B/C/D are the only valid options) and “knowledge” (the model knows which of options A/B/C/D are incorrect) could be to let the model write a full sentence, and then ask another model which option the first model selected.
What’s the layer-scan transformation you used?