When I first started tutoring reading for the SAT and the ACT, I took a lot of things for granted. I assumed, for example, that my students would be able to identify things like the main point and tone of a passage; that they would be able to absorb the meaning of what they read while looking out for important textual elements like colons and italicized words; and that they, at bare minimum, would be able to read the words that appeared on the page and sound out unfamiliar ones.

Over the last few years, however, I’ve progressively shed all those assumptions. When I start to work with someone, I now take absolutely nothing for granted. Until a student clearly demonstrates that they’ve mastered a particular skill, I make no assumptions about whether they have it. And that includes reading the words as they appear on the page.

To be sure, many of the students I’ve worked with do have most of the basics down — I’ve only worked with a few who had striking difficulties sounding out words. But on the other end of the spectrum, I can also count on one hand the number of students I’ve worked with who truly read at an adult level. Unsurprisingly, most of them required no more than a handful of sessions to score in the 750-800 range. In between, of course, there’s a vast, uneven middle ground, usually corresponding to mid-500s to high 600s on the SAT, and 23-28 or so on the ACT.

Within that very large group, though, I’ve noticed that most students fall into one of three general subgroups. The division isn’t clear-cut, but still, I find it’s a helpful way to think about things. Sometimes a student missing some of the lower-level skills will simultaneously have some of the higher-level ones (I once worked with a whip-smart girl who had serious decoding problems but a stellar sense of logic), but very often, a lack of skills at one level translates into an inability to master skills at the next level.

1) Decoding

Students in this group typically learned to read through a whole-language approach and have had minimal exposure to phonics. Having never learned to match letters or combinations of letters to specific sounds, they recognize words by memory and are forced rely on guesswork when they encounter an unfamiliar ones. Often, they think by process of association. If an unfamiliar word starts the same way as a familiar one, they’ll simply plug in the one they know. For example, if they see an unknown word like prodigious, they might read productive, or they might read argument instead of augment. Interestingly, they tend not to notice whether the words they’re plugging in make grammatical sense in context.

Because they’re not reading the words that are actually on the page, these students can completely misinterpret what they’re reading. But in addition to that, it’s almost impossible for them to use roots, prefixes, suffixes, etc. to make logical assumptions about unfamiliar words because they can’t even recognize when roots are being used. Lack of knowledge about how words are put together feeds incomprehension.

2) Vocabulary

At a somewhat more advanced level are the students who can decode competently but lack the vocabulary knowledge to make sense out of what they’re reading. I’ve actually found that many students with learning disabilities fall into this category. Kids without any evident weaknesses can often slide by in school, whether they’ve learned to decode 100% reliably or not, and so their problems go undetected. In contrast, students with obvious reading difficulties are noticed and often given explicit instruction in phonics. The result is that they learn to sound out difficult words beautifully but have no idea what they mean!

For many of these students, direct instruction in vocabulary and roots can boost their comprehension considerably — if, that is, they’re willing to put in the time.

3) Context

These students are adept decoders and often have relatively strong vocabularies, but they have difficulty making the leap from comprehending the literal words to understanding their larger significance (which would in turn allow them to identify right answers quickly and securely). Typically, they lack the broader contextual knowledge that would allow them to connect the content of specific passages to larger debates, discussions, and themes in the real world.

While some of these students can learn to strategize well enough to pull themselves in the low 700s, others stay stuck in the mid-high 600s on the SAT and below 30 on the ACT because they can’t get to the big picture from the details. What looks like a timing or a strategy problem is actually indicative of something deeper. But these students only have a reading problem in the sense that they don’t have enough context to pull together all the pieces. What they really have is a knowledge problem. And in the short term, there’s no way to compensate for that.