MSSC CPT common mistakes
MSSC CPT · Understand the traps and how to avoid them.
Selects the most protective-sounding option (respirator, face shield, steel-toe boots) any time a hazard appears in the stem, even when the question asks for the first step, the best control, or the employer's initial action.
Everyday instinct says 'more PPE = safer,' so the strongest-sounding answer feels correct. The exam often tests the hierarchy of controls, where PPE is the last line of defense, not the first choice.
What to do instead
Before reading the options, restate the stem as 'which level of control' (elimination, substitution, engineering, administrative, PPE). Cross out any PPE answer unless the stem says the hazard cannot be engineered out or asks specifically about PPE selection or use.
Treats lockout and tagout as interchangeable, and when asked who may remove a lock chooses 'the supervisor,' 'anyone on the crew,' or 'whoever is available at shift change.'
Tagout is often described casually in training as a 'tag instead of a lock,' which blurs the rule that the person who applied the lock is the one who removes it.
What to do instead
Memorize the LOTO sequence in order: notify affected employees, shut down, isolate all energy sources, apply lock and tag, release stored energy, verify zero energy. Then drill the removal rule: only the person who applied the lock removes it; supervisor removal happens only under a documented exceptional procedure with verification the area is clear.
Picks a water (Class A) extinguisher for a live electrical panel or a cooking-oil fire, or picks a Class B unit for ordinary combustibles like paper and wood.
Candidates memorize the letters A-B-C as a list without pairing each letter to the fuel type it covers, so the letters become interchangeable labels at test time.
What to do instead
Build a small fuel-to-class table and rehearse it: A = ordinary combustibles, B = flammable liquids, C = energized electrical, D = combustible metals, K = kitchen grease. Lock in the two red-flag rules (never water on electrical or grease) and classify five sample materials out loud before the test.
Uses 'accurate' and 'precise' as synonyms, labeling a tight cluster far from the target as accurate, and answering repeatability questions with the definition of reproducibility.
The two words are used interchangeably in casual speech, and both sound like 'good measurement,' so the option that contains the word the candidate recognizes gets chosen.
What to do instead
Anchor on a target analogy: accuracy = closeness to the true or reference value; precision = how tightly repeated readings cluster. Then split the second pair: repeatability = same operator, same gage, same part; reproducibility = different operators or setups. Sort each answer option into one of the four buckets before selecting.
Judges process stability against specification limits, calling a point 'out of control' because it fell outside the customer tolerance, or calling a drifting process 'in control' because every point is still inside tolerance.
Tolerance is the number candidates see every day on the shop floor, so spec limits feel like the natural yardstick. Control limits are computed from the process itself and are usually tighter.
What to do instead
State the source of each limit before answering: control limits come from process data (center line plus and minus three sigma); specification limits come from the customer drawing. Then apply the chart rules (a point beyond a control limit, a run of seven or eight on one side, a clear trend or cycle) rather than comparing to print tolerance.
Chooses the wrong quality tool for the verb in the stem: a Pareto chart when the question asks what is causing one specific defect, or a histogram when the question asks which few problems to attack first.
Pareto, histogram, and fishbone all look like 'quality charts' in review material, and candidates match on the topic (defects) instead of on the task (rank vs. brainstorm causes vs. show distribution).
What to do instead
Convert the stem to a verb first, then match: rank or prioritize by frequency, Pareto; brainstorm or organize possible causes, cause-and-effect (fishbone); show spread or shape of data, histogram; show behavior over time, run chart; show correlation between two variables, scatter diagram. Choose last, after the verb is fixed.
Computes takt time from the time it takes to build one unit, or computes OEE using only availability times quality and leaving out performance.
Takt and cycle time both describe 'time per unit' and get swapped verbally on the floor, and OEE's three factors are often reduced in memory to the two that are easiest to observe.
What to do instead
Write the formula on scratch paper before touching the calculator: takt time = available production time divided by customer demand; cycle time = actual time to complete one unit; OEE = availability times performance times quality. Label the units of the result (seconds per unit vs. percent) and check that the answer makes sense against the demand number.
Accepts inspection, material transport, storage, or waiting as value-added because the step is required or appears on the routing, and cannot sort a described activity into the correct waste category.
'Required by the procedure' feels equivalent to 'adds value,' and lean waste categories overlap in everyday descriptions, so the first plausible category wins.
What to do instead
Apply the value-added test: does the customer pay for this step, and does it change form, fit, or function correctly the first time? If not, it is non-value-added no matter how necessary. Then name the waste explicitly (overproduction, waiting, transport, overprocessing, inventory, motion, defects, underused talent) and check the stem's verb against that list.
Labels vibration analysis or infrared thermography as preventive maintenance, or labels a calendar-based lubrication route as predictive maintenance, when asked to classify a maintenance activity.
Both terms start with 'pre' and both are described as 'proactive' in review material, so the classification collapses into a coin flip under time pressure.
What to do instead
Sort by trigger, not by name: preventive = triggered by time or usage count (scheduled lube, filter change, planned inspection); predictive = triggered by condition data trending toward a limit (vibration, thermography, oil analysis, ultrasound); corrective = after failure; reactive/run-to-failure = deliberately deferred. Ask 'what caused us to act?' and the category follows.
On troubleshooting items, jumps to 'replace the motor,' 'replace the valve,' or 'call maintenance' instead of choosing the diagnostic step, and does not distinguish an overload trip from a short circuit or a pressure problem from a flow problem.
Replacing parts is the visible action on the floor and feels decisive, while 'measure voltage at the disconnect' feels like a non-answer. Diagnostic steps are also the longest, least familiar options.
What to do instead
Before choosing, ask 'which measurement would confirm this?' and prefer the option that gathers evidence (voltage at the source, checking for a blown fuse or tripped overload, reading pressure at the gauge, verifying flow with a flowmeter over guessing at the component). Also fix the common pairs: overload = sustained excess current, short circuit = fault current path; pressure is resistance to flow, flow is what moves the actuator.