HCD.28:5.1 - Future diagnosticians who calculate correctly but choose the wrong model

This is a constructed design, not a report of a delivered course or measured gain.

An author plans a module for 24 future technical diagnosticians. The audience hypothesis is that they can calculate energy per unit volume but may treat a rise in that ratio as proof of one cause. The later contribution is to name plausible rival explanations, choose an observation that distinguishes them, and recommend only the action the evidence supports. Safe case data and the subject answer basis come from a qualified domain contributor.

Use the pump family in HCD.5/.6. A baseline of 20 kW at 100 m³/h becomes 22.4 kW at the same flow. The ratio rises by 12%; that calculation does not select increased hydraulic resistance over changed efficiency or a measurement explanation. The teaching route must make that missing selection visible. It does not promise a unique cause when the data leave several possible.

The author’s first diagnosis changes the next work:

• If the expert’s source already explains how the pressure observation distinguishes the models, use that basis to design a contrast and a choice task.
• If the expert can choose but cannot explain the decisive relation, obtain reconstruction and another-case scrutiny before presenting the rule as established.
• If the material states the relation but buries the relevant conditions in unrelated detail, repair the material and inspect the affected reader use.
• If the learner needs that explanation but no qualified help is available within the feedback window, repair supply.

Begin with a 90-minute core route: 20 minutes for an entry check and worked contrast, 10 for a first judgement, 30 for reason comparison, 10 for a changed case, 15 for feedback and correction, and 5 for a return plan. These are planning allowances to test in use. A separate 20-minute unit-support branch returns to the same whole diagnosis task. If six entrants need it, the branch adds two learner-hours. The supported individual construction below retains the ninety-minute core; the four-person construction needs six additional active minutes for qualified help. Neither removes correction or another required personal action to keep the initial estimate.

Compare two serious constructions. In A, each person works with qualified contrasting reasons and requests individual subject help. In B, small groups compare evidence through HCD.22 before the same kind of individual changed-case task. Keep the outcome and final assistance conditions comparable. If A cannot elicit the needed response to another person’s objection, enrich that interaction or mark the narrower contribution; if B exposes fewer relevant contrasts, do not assume its social format fills the gap.

Suppose both need six hours to qualify the common cases and two further hours for their respective materials and preparation. Both retain eight minutes of individual checking per entrant: 192 minutes for 24 people. A provisionally needs 24 six-minute help appointments, or 144 minutes distributed across bookable windows. B needs six six-minute group interventions: 36 minutes of direct demand. One mentor cannot meet that total during a thirty-minute booking. HCD.20:5.1 gives the compatible repair: two mentors remain booked for 11:00–11:30, while pairs of four-person groups start at 10:50, 11:00 and 11:10. Each group performs twelve minutes of initial explanations, six of help, twelve of second personal contributions and six of reconciliation. The visits occur at 11:02–11:08, 11:12–11:18 and 11:22–11:28 for each mentor. All inputs for a visit exist before it starts, four-minute gaps support movement or connection, and every group has time to use the response. These 36 active group minutes extend B’s core to 96 minutes. Confirm each group’s own start and finish; a single common thirty-minute availability window would not support this construction.

Complete the comparison for one cohort with the following explicit allowances. Treat eight minutes per person as the first-response check and preparation of usable feedback; allow four further minutes to inspect the correction and return its bounded result. Preparation of the unit-support material and provider briefing is inside the eight fixed hours above. Actual help for the six entrants using that branch requires another four provider-minutes each, inside the learner’s twenty-minute branch activity.

These are constructed planning allowances. The 48/72 coordination minutes cover this cohort’s scheduling, missing submissions and result distribution; they do not repeat fixed material production or the already booked group window. The recovery reserve can supply six interventions of eight minutes in A and nine of eight minutes in B. Reserving that time counts as provider allocation even if not all of it is used.

Make the feedback usable within an agreed two-day route:

• Before the main work, the six relevant entrants complete the twenty-minute branch and receive their booked help. The 20-minute core preparation and 10-minute first judgement precede reason comparison.
• In A, book the 24 complete six-minute subject-help appointments between 09:00 and 11:24 on day one. Each learner starts their thirty-minute comparison twelve minutes before their appointment: twelve minutes comparing the supplied reasons, six receiving help and twelve using the response. A prepared common channel and preloaded case make opening and closing part of that complete appointment; extra setup would require extra booking. The last comparison ends at 11:36. In B, follow HCD.20’s named assignments and staggered group starts; groups finish at 11:26, 11:36 and 11:46. Their later personal responses finish at 11:36, 11:46 and 11:56. The mentors’ 60 booked minutes contain the 36 direct minutes and all stated transition gaps.
• All 24 ten-minute personal responses are available by noon. One qualified assessor has 14:00–17:12 for the 192 minutes of first-response checking and feedback. Each learner receives the feedback by 09:00 on day two.
• Learners read the feedback and correct within their fifteen-minute activity, submitting by noon on day two. The assessor has 13:00–14:36 for the 96 correction-checking minutes and returns the bounded results by 15:00. Each learner then uses the five-minute return-plan activity by 18:00.
• A prepared provider has the 48-minute A reserve or 72-minute B reserve from 15:00 for unresolved corrections or restored missed opportunities. If the demand exceeds that reserve, obtain additional viable help or return the resulting limitation; the timetable does not license reporting every entrant as successful.

A’s ninety-minute core uses 36 learner-hours; B’s ninety-six-minute core uses 38.4. Add two hours to each for the six preparation branches. Reserve a further fifteen learner-minutes for each possible recovery intervention: up to 1.5 hours in A and 2.25 in B. The corresponding active-time allowances are therefore 39.5 and 42.65 learner-hours if all reserved recovery is used. Elapsed waiting for feedback remains visible in the two-day schedule; it is not added as active practice, and the route is unsuitable if the receiving use requires completion on day one.

Under these assumptions B allocates 36 fewer provider-minutes but 189 more active learner-minutes at full recovery use. Neither dominates on both coordinates, and the comparison has not established equal learning quality. A new cohort repeats the recurring contributions; it shares fixed preparation only while cases, criteria and provider readiness remain usable. The four specialist-hours inside the pump problem are simulated task constraints, not 24 purchases of live measurements. A product using real measurement work must add that actual supply and its conditions.

This finished accounting exposes the next dependency: 288 minutes of checking and correction checking remain in both variants. Discussion does not remove them. Use actual first responses, correction needs, coordination and recovery demand to replace the estimates before relying on a stronger capacity or cost claim.