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The POSS test

Plant Operator Selection System

EEI's catalogue describes POSS as covering operator jobs in fossil, nuclear and hydroelectric power plants.

Take a full POSS mockFree demo: Reading for Comprehension
Sections
4
Questions
118
Timed testing
67 min

As published in EEI's POSS test brochure.

The sections, in order

Each section has a free demo you can try now. Counts and time limits are the ones EEI's POSS brochure publishes for this battery — the same section can be timed differently in another one.

  1. 1.Reading for Comprehension

    Standard36 questions · 30 min

    You read passages of the kind of writing the job involves — procedures, safety rules, equipment descriptions, work instructions — and answer questions on each. The wrong options are usually true-sounding statements the passage does not actually support, so the discipline is answering from the text rather than from what you already know.

    Five passages.

    Free demo Full practice

  2. 2.Mechanical Concepts

    Standard44 questions · 20 min

    Simple pictures of mechanical arrangements with a short question: which gear turns which way, which pulley takes less effort, where the pressure is highest, which load is more stable. No formulas are needed and nothing is measured; it is about understanding how everyday mechanisms behave.

    Free demo Full practice

  3. 3.Mathematical Usage

    Standard18 questions · 7 min

    Short applied math: convert units, put numbers into a given formula, work out a rate, a percentage or an area. Individually the questions are easy. The section is built around speed, so the practice that matters is doing simple arithmetic quickly and cleanly.

    Short form; a long form of 46 in 17 min also exists.

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  4. 4.Figural Reasoning

    Complete20 questions · 10 min

    Sequences and sets of abstract figures where something changes step by step — a shape rotates, a count grows, a shading alternates. You work out the rule and choose the figure that continues it, or the one that does not belong. No words, no numbers, and a very short clock.

    Series, comparison, progression.

    Free demo Full practice

About the POSS test

POSS is the battery EEI describes for operator jobs in fossil, nuclear and hydroelectric plants — power plant operator, control room operator, nuclear reactor operator. Its brochure sets out Reading for Comprehension (36 questions on five passages in 30 minutes), Mechanical Concepts (44 in 20), Mathematical Usage and Figural Reasoning (20 in 10).

One detail resolves a lot of confusion online. EEI publishes POSS as two alternate batteries that "differ slightly in content and administration time", and the only documented difference is the math: a short form of 18 questions in 7 minutes, or a long form of 46 in 17. That is where the widely quoted range of 118 to 146 questions and 67 to 77 minutes comes from. Which one you sit is decided by the employer and the role.

Figural Reasoning is the section worth extra attention, because it appears in no other battery we cover and there is very little free material for it anywhere. Twenty abstract pattern items in ten minutes rewards having a search routine rather than a flash of insight.

How it is scored

EEI's POSS brochure describes an aptitude index score from 0 to 15, with no penalty for guessing. As with every EEI battery, the cut score is the employer's and is not published.

Worth knowing

  • The only documented difference between the two alternate POSS batteries is which Mathematical Usage section is used.
  • EEI's brochure notes that the battery used for nuclear roles differs somewhat.
  • Some utilities administer POSS and MASS together as one longer session — one names the combination a General Power Plant Battery.

Common questions

How many questions is the POSS test?
EEI's brochure describes two alternate batteries: 118 questions in 67 minutes of timed testing with the short Mathematical Usage section, or 146 questions in 77 minutes with the long one. Everything else is the same.
How is POSS scored?
EEI's brochure describes an aptitude index score from 0 to 15 — a different scale from CAST's 1 to 10, which is why score talk from line worker candidates does not transfer. There is no published cut score.
Do I sit POSS or MASS?
POSS is described for operating the plant, MASS for maintaining it. Some utilities administer both to the same candidates as one longer session. Your invitation letter will say which sections to expect.

Utility Tests is independent practice. We are not affiliated with, endorsed by or connected to the Edison Electric Institute or any utility, our questions are original and written from published descriptions, and nothing here is the real POSS test.