doomer

Reading about the actual tiers that test grades participants into, I'm not sure if "can read books for adults" is an accurate description of what tier 4 (which starts at a score of 65%) and above is determining, nor where the sample questions (all of which were extremely simple, straightforwards texts and tasks) fall on it:

At level 4, adults can read long and dense texts presented on multiple pages in order to complete tasks that involve access, understanding, evaluation and reflection about the text(s) contents and sources across multiple processing cycles. Adults at this level can infer what the task is asking based on complex or implicit statements. Successful task completion often requires the production of knowledge-based inferences. Texts and tasks at Level 4 may deal with abstract and unfamiliar situations. They often feature both lengthy contents and a large amount of distracting information, which is sometimes as prominent as the information required to complete the task. At this level, adults are able to reason based on intrinsically complex questions that share only indirect matches with the text contents, and/or require taking into consideration several pieces of information dispersed throughout the materials. Tasks may require evaluating subtle evidence-claims or persuasive discourse relationships. Conditional information is frequently present in tasks at this level and must be taken into consideration by the respondent. Response modes may involve assessing or sorting complex assertions.

It may be a little stricter of a requirement, since it sounds like at levels 4 and 5 the questions are frequently forcing guesses based on inferred information, and notably the highest tier only requires a score of 75% so even someone who is considered fully literate to as much as is feasible to test is still expected to/allowed to fail a bunch of the hardest questions.

I'm really not sure what the lower tiers look like in practical terms: "below level 1" is clearly like a grade school level or below, level 1 itself is maybe grade school level? Maybe 2 and 3 are more highschool level proficiencies? I really don't know what's expected of people or normal at a given level. It seems like the threshold for tier 4 is around the level of "graduated highschool with reasonably good language comprehension abilities" though.

There's also this note alongside the scale, which confirms my assumption that even proficient people are expected to fail a lot:

NOTE: Every test item is located at a point on the proficiency scale based on its relative difficulty. The easiest items are those located at a point within the score range below level 1 (i.e., 175 or less); the most difficult items are those located at a point at or above the threshold for level 5 (i.e., 376 points). An individual with a proficiency score that matches a test item’s scale score value has a 67 percent chance of successfully completing that test item. This individual will also be able to complete more difficult items (those with higher values on the scale) with a lower probability of success and easier items (those with lower values on the scale) with a greater chance of success.

In general, this means that tasks located at a particular proficiency level can be successfully completed by the “average” person at that level approximately two-thirds of the time. However, individuals scoring at the bottom of the level would successfully complete tasks at that level only about half the time while individuals scoring at the top of the level would successfully complete tasks at the level about 80 percent of the time. Information about the procedures used to set the achievement levels is available in the OECD PIAAC Technical Report.

SOURCE: OECD 2023 Survey of Adult Skills International Report

What % of adults do you know that read a single book every year? Even multiple years. I'm willing to bet it's a lot lower than you think.