HESI A2 common mistakes
HESI A2 · Understand the traps and how to avoid them.
On inference and main-idea items, selects the answer choice that repeats wording from the passage instead of the choice that is supported but paraphrased.
Familiar wording feels safe under time pressure, so the test-taker pattern-matches phrases rather than testing the logic of the claim against the text.
What to do instead
For every choice, point to the sentence that supports it and say the support out loud in your own words; eliminate any choice you cannot tie to a specific sentence, even if it echoes the passage.
Chooses the most common everyday meaning of a vocabulary word even when the sentence uses a secondary sense (e.g., 'the patient was critical' read as 'judgmental').
Recognition of a familiar definition produces a fast, confident answer, so context is skipped entirely.
What to do instead
Substitute each answer choice into the original sentence and read the full sentence back; only the choice that keeps the sentence logical survives.
Matches the verb to the noun nearest it instead of the real subject when a prepositional phrase sits in between ('The box of tools were...').
Proximity is what the ear hears, and casual speech tolerates agreement errors that standard written English does not.
What to do instead
Before checking agreement, bracket and mentally delete every prepositional phrase, then read subject and verb alone; repeat for pronoun-antecedent items.
Builds a proportion or dosage calculation with mismatched units (mg on one side, g on the other; cm versus m) and then picks the choice that matches the raw number.
The numbers look right and a distractor was built from exactly that unconverted number, so the error is reinforced by seeing a matching option.
What to do instead
Write the unit next to every number in the setup and cancel units across the equation before dividing; if the units left over are not the units asked for, the setup is wrong.
Computes the correct value of x but answers with x when the question asked for 2x, the total, the remainder, or the difference.
Solving feels like finishing, so the final step gets skipped, and the intermediate value is deliberately offered as a distractor.
What to do instead
Before calculating, underline the exact quantity requested and write it at the top of your scratch work; make the last line of work a check that the number you are about to select is that quantity.
Uses 'diffusion' and 'osmosis' interchangeably and describes solutes as moving by osmosis, or says water moves by active transport.
Both terms are taught together as passive movement, so the distinction collapses into a single fuzzy concept.
What to do instead
Before answering, name the particle that moves (water vs. solute) and whether it is going down its gradient; osmosis is only water across a semipermeable membrane.
Reads mole ratios directly off the equation as written, without balancing it first.
The coefficients are already there and look usable, so the balancing step feels optional rather than mandatory.
What to do instead
Balance the equation and rewrite it with final coefficients before touching any ratio; treat an unbalanced equation as an unfinished problem.
States that the pulmonary artery carries oxygenated blood because arteries are assumed to be oxygen-rich.
The artery/vein rule is learned as a slogan tied to oxygen content rather than to direction of flow relative to the heart.
What to do instead
Define artery and vein only by direction (away from vs. toward the heart), then trace any vessel from the right ventricle or left atrium to determine its oxygen status.
Credits the stomach or large intestine with most nutrient absorption, or assigns the small intestine only a water-absorption role.
The stomach is the most salient digestive organ and the colon's water function is memorable, so the small intestine's dominant absorptive role gets crowded out.
What to do instead
Build a one-line function map (mouth = mechanical/amylase start, stomach = acid and pepsin, small intestine = most absorption via villi, large intestine = water and electrolytes) and recite it before physiology items.
Substitutes centimeters, grams, or minutes straight into formulas that require SI units, then reports joules or newtons from the raw numbers.
The numerical values are given in the problem stem, and converting them feels like extra work with no visible payoff.
What to do instead
Convert every given value to meters, kilograms, and seconds as the first written step, label each converted value, then substitute; check the final unit dimensionally.