Reasoning systems can spend extra inference compute on a longer response, multiple independent candidates, verification, or an explicit search procedure. These are different mechanisms. A single autoregressive trace does not automatically implement tree search, and visible reasoning text is not a complete account of a model's internal computation. Tags such as <think> are formatting conventions used by some models, not a universal reasoning architecture.
Separate training-time improvement from inference-time allocation. A trained policy determines what candidates are available. A selection rule determines which candidate becomes the answer. A verifier can help only when its errors are sufficiently controlled; otherwise additional candidates can increase the chance of selecting an answer that exploits the verifier.
Compare like with like
Fix a task set and a total compute or latency budget. Compare one longer sample, several short samples with majority voting, and several samples ranked by a verifier. Record accuracy, generated tokens, wall time, and verifier cost. Keep prompt selection and verifier tuning off the test set. Report both average performance and hard subgroups.
For independent trials with identical success probability p, the probability that at least one of k candidates succeeds is 1−(1−p)^k. This is an oracle availability calculation, not deployed answer accuracy: an actual system still has to identify the successful candidate. Correlated samples and imperfect selection break the simple operational interpretation. More budget can yield diminishing returns, saturation, or worse selected answers.