Taxonomy I
Taxonomy II
Taxonomy III
Taxonomies I - II - III
Taxonomies II - III
Appendix A – Units of measurement and symbols
Appendix B – Special characters
Appendix C – Standard spellings for terms with prefixes
Appendix D – Style guide development history

3. TAXONOMY III

A. Rules governing STEMS only

3.1 – What happens, correct the problem, cause and effect, calculations

Taxonomy III items are usually ‘cause and effect’ or require the candidate to perform multiple tasks, such as:

  • complex calculation
  • complex calculation + diagram
  • complex calculation + codebook reference
  • codebook reference + diagram
  • complex calculation + diagram + codebook reference


Taxonomy III stems are normally worded in the following manner:

  • What is the cause / problem / result of X?
  • What is done to prevent / correct / repair the problem? *
  • X was incorrectly installed. What is the result?
  • Refer to Diagram  2. How many Y are required to do X?

    Diagram and complex calculation
* NOTE: The correct phrasing is ‘What is done to correct the problem?’ not ‘What is the procedure’. A procedure does not represent critical thinking or problem solving, but application of knowledge – thus it is a Taxonomy II question.

Correct examples
  • Refer to Figure 4. What is the problem in the series control circuit?

    1. High ECU sensor supply voltage.
    2. Low ground circuit resistance.
    3. High supply circuit resistance.
    4. Low ECU sensor supply voltage.
  • A solvent-borne metallic colour is being matched. The air pressure is too high. What is the result?

    1. Darker colour.
    2. Lighter colour.
    3. Change in hue.
    4. Inadequate coverage.
Agricultural Equipment Technician item referring to a diagram and requiring problem solving. Automotive Refinishing Technician item requiring analysis.
  • Refer to Figure 84. Given the following information:

    • A: 2 7/8 in. OD
    • B: 2 3/8 in. OD
    • C: 1 1/4 in. OD
    • Pipe insulation: 2 in.
    What is the length of steel plate required to fabricate the trapeze support?

    1. 20 1/2 in.
    2. 22 1/2 in.
    3. 24 1/2 in.
    4. 26 1/2 in.
  • During testing, a 600 V, 125 hp, 1 800 rpm synchronous motor has an 80% power factor. What is the maximum breaker size?

    1. 225 A
    2. 250 A
    3. 300 A
    4. 350 A
Construction Electrician codebook item referring to a diagram and requiring a complex calculation. Industrial Electrician codebook item requiring a complex calculation.
NOTE: When there is disagreement with a formula or calculation provided in the formula sheet of the exam booklet, seek consensus among all workshop participants and provide the correction and rationale to the Host or ESDC Advisor.
NOTE: When a stem provides context (e.g. conditions, scenario, data), the information is provided first and the stem ends with the interrogative. Refer to 5.2 — Multiple statements + question for examples.