It depends. I’m sorry, but it does.
There are essentially two opposing strategies for passage-based questions: read the passage first or read the questions first and consult the passage as the questions demand.
Probably the most widely advocated strategy is to split the difference, and to read the passage first, favoring speed over retention of details. Princeton Review, for instance, encourages you to “read what you need” without “getting mired down in all the little details.”
The problem with this approach is that it tacitly asks you to distinguish between important and unimportant words and information as you read (quickly!), while there is certainly no guarantee that a question will not invoke some relatively minor detail. A too-quick reading, in other words, might be a waste of time.
Yes, you can and will go back to the passage when asked about a specific word, but in the case of other sorts of questions, why read recklessly if you will eventually need to read diligently? If you are asked something like, “The revelation that this incident was the only time the author fainted during the war serves to __________,” you can either be in the position of looking at the passage for the first time and knowing what you need to find or having formed an idea of what the answer is and then going back to verify. But there is really no good argument for having read the passage without having marked that detail.
So, we’re back at our original options.
Depends on what?
If critical reading and/or literature is a strength of yours, read read the passage first. A strong reader is one who can analyse on the fly, who can not only understand generally what is being discussed, but how the passage is structured and where its ideas unfold. A strong reader would read a phrase like “for the first and last time during the trials that surrounded me for four years, I fainted away,” and instinctively recognize a point of emphasis. If this describes you, look at the questions first (without worrying about the answer choices) and then just go ahead and read the whole passage. This is the approach you should aspire to take.
But, if you find critical reading to be among the more difficult sections, you may be better off going question by question. For very specific questions, reading the question then the passage is really the only way to go. “In line 31, the word spends most nearly means____,” is a question that depends on immediate context but no further. Questions like the one above can also often be answered by close reading of the paragraph, or the handful of lines around where the referenced text appears. Your goal, in this approach, is to privilege the answers you can get without really considering the passage as a whole.
In both approaches, you should leave the big picture questions until the end. Inevitably, you will be asked a question like, “The author’s tone in this passage can best be described as ____.” If you’ve read in advance, you’ll certainly have an answer in mind before seeing the choices. If you haven’t, you may feel like the only way to answer this is to read the whole thing carefully (and if you feel okay about time, you can). But these kinds of questions are asked first as often as they are asked last, for no reason other than to disorient the test-taker. If you make a point to leave them for the end (making sure to leave a mark where you’ve skipped the bubble, to be erased when you do fill it in), no matter what approach you’ve taken, the other answers, and the other choices you’ve been provided, will give you some sense of potential coherence. It is unlikely that the “tone” or “argument” of the passage will be completely out of line with the parts of it you have been asked to consider.
The goal, in either approach, is to make reading count. Try out these approaches on practice tests and figure out what approach gives you the most confidence in your answers within the given time frame. Confidence is key. Don’t go by the number of correct answers at first; the approach that feels right is usually going to be the more effective one over many trials.
Finally, a note on reading speed: a lament I hear frequently as a professor of literature is that reading simply takes too long. Students often ask if I have any “speed-reading tricks.” It is possible to train yourself to read faster with certain exercises, but these exercises effectively amount to reading a lot. People who are unable to read a page or so of text without falling behind on time are frequently people who simply don’t read very much outside of their assigned work. One of the best ways to be prepared for a standardized test is to be a regular reader of fiction, long-form journalism, and/or popular science and philosophy. There are strategies for taking reading comprehension tests, but being an efficient reader with strong powers of retention is a real-life skill!