There’s probably no other GMAT question type that instills more fear in candidates than data sufficiency. It’s unique to the GMAT and evaluates a candidate’s ability to discern when s/he has enough information to come to a conclusion. And those who are able to efficiently and successfully tap into those higher-order reasoning skills are ultimately rewarded accordingly. Let’s take a look at a few tips to help you decode data sufficiency:
Familiarize yourself with the answer choices.
Just like the AWA and every other section, the instructions and more importantly, answer choices for data sufficiency don’t change. Your inclination might be to read the answer choices every time which will only waste time that you could be spending reading and analyzing the individual statements. As you’re practicing, you may consider rewriting the answer choices on your noteboard without the “extra text” (see below). It will remind you to focus on the statements only and with which answer choice each corresponds.
Look at the statements separately.
One of the easiest traps to fall into is evaluating one statement and then the second, but carrying over information and implications from the first statement. It’s crucial to not fall into the “what if” game or allow statement 1 or influence statement 2 (or vice versa). One way to combat this is to pick the “simpler” statement after reading the prompt and question. If the simpler statement isn’t sufficient, that will automatically eliminate at least two answer choices and make your task a bit easier. Be careful to not fall for what may feel like an obvious or slam-dunk answer, and it may sound overly simple, but make sure your answers (and the statements!) don’t contradict each other. Don’t solve for x.
In most quant courses, you’re hard wired to solve for x, or y, or some number. Data sufficiency isn’t asking you to solve the question though; it’s asking you to discern when you have enough information to solve the problem. In most cases, you can reason your way to the answer so make sure you’re not wasting valuable time solving the problem when you just need to determine what is needed to solve the problem. Remember, pacing is crucial so move quickly and efficiently!
The GMAT is ultimately a test of higher order reasoning skills, so those test takers who are able to successfully navigate the data sufficiency waters will be rewarded when they receive their unofficial score report. | 
