Consider: METR: Measuring AI Ability to Complete Long Tasks

METR’s “Measuring AI Ability to Complete Long Tasks” paper uses “a combination of RE-Bench, HCAST, and 66 novel shorter tasks” to measure “50%-task-completion time horizon”, which is defined as:

This is the time humans typically take to complete tasks that AI models can complete with 50% success rate.

The purpose of this metric is forecasting AI capabilities over time (as of November 2025, it fits a nice exponential trend line with ~7 months doubling time). But people often take the metric’s description literally and might miss out on the nuance.

E.g. the current leader on the graph is GPT-5.1-Codex-Max with task length estimate of 2 hours 41 minutes at 50% success rate. For an 80% success rate (which METR also reports) the task length is only 31 minutes. So people take it to mean that frontier models can only handle basic tasks.

This contradicts reports that frontier LLM coding agents are able to perform rather complex tasks, e.g. “one-shot” a game which can take experienced developers weeks to implement. Some people tend to dismiss these reports using “it must be in the training data” argument (it’s rather hard to assess what kind of games or web sites are actually in the training data). But we also have serious programmers reporting on serious tasks taken on by LLMs, e.g:

Let’s look deeper into what METR’s metric actually represents:

For each model, we can fit a logistic curve to predict model success probability using human task length.

So it’s not particularly easy to map it to specific task performance, especially in the case of RE-Bench where human baseline is based on a 8-hour human work effort.

When METR applied their methodology to their own human baseline raw data (i.e. without a success filter), they got 1.5 hours for 50% success rate. I.e. if we use this methodology against human experts hired by METR, we can “conclude” that humans can do only 1.5 hour tasks at 50% success rate. (I feel like this generally confirms common wisdom that human devs are also rather unreliable.) Here’s are relevant quotes from the paper:

We aggregate human baseline times into a task length rating by taking the geometric mean time of successful baseline runs

We chose to filter successful runs for two main reasons … Secondly, we wanted to exclude cases where the baseline failed for reasons that are not applicable to models. A substantial fraction of human failures appeared to fall in this category - including humans having insufficient expertise for the task, or giving up on a task for unclear reasons

Human time horizon: An alternative approach would be to calculate the human time horizon using the same methodology as we do for models. One natural interpretation of time horizon would imply that the time horizon of “a human given x hours” is x hours. Since our baseliners were paid for spending up to 8 hours per task, we would expect their time horizon to be around 8 hours. However, in practice it’s much lower, at around 1.5 hours (which would imply that the best models will surpass humans in under 7 months). As discussed above, we think this is artificially low, given that many human failures seemed to be artifacts of our incentive scheme.

In other words, humans were given benefit of doubt, but models aren’t. METR recognizes that it introduces a bias:

However, conditioning on success biases towards shorter task length ratings, thereby underestimating model performance.

But, of course, this does not matter much for forecasting purposes where you care more about relative progress rather than what the absolute number represents. But it matters if we do “LLM vs human software engineer” comparison.

In other news, raw human baseline was surpassed by GPT-5, and, perhaps, even o3, back in April 2025, 6 months ahead of what METR anticipated (the best model at the time the paper was written was Sonnet 3.7, now clearly known as rather defective when it comes to agentic coding).

As we are approaching singularity, we are no longer able to process and understand the entirety of available information.