The Necessary Tangle

Systemic intervention | about 45 minutes | free

Futures and probes: test robustness without pretending to predict

Compare options across explicit scenarios, then design more than one bounded learning probe.

Framework link: Systemic inquiry and intervention design: futures, uncertainty and complexity. Apprenticeship practice links: K1, K2, K3, S2, S3, S7, B3, B5, B6.

What this exercise can and cannot establish

A bridge to apprenticeship duties 8-10. Scenario analysis, sensitivity testing and safe-to-fail probes are distinct activities; none is a guarantee about the future.

This is original learning material, not a reproduced official course. Mechanical checks have determinate answers within the stated case. Worked comparisons for open judgements show defensible reasoning, not the only possible model. Specialist pedagogical review is not recorded.

The case

Fictional case: an advice service is choosing capacity arrangements. Scenarios are low demand at 80 cases/week and high demand at 140. Option A has fixed capacity 100; option B has fixed capacity 120; option C has baseline 90 and can add 60, but only after two weeks. Costs and case complexity are not supplied. Separately, the service does not know whether residents avoid appointments because of timing, lack of trust or confusing letters. No one can safely be denied essential support for an experiment.

Work through it

Use paper, your own drawing tool or the notes below. Attempt each step before opening its comparison. Describe a diagram in words when that is more accessible.

  1. 1. Calculate the initial capacity gap under each demand scenario.

    Produce: A two-by-three table, treating C's delay explicitly.

    Compare your work for step 1

    At demand 80, all options cover demand initially: spare capacity A=20, B=40, C=10. At demand 140, initial shortfalls are A=40, B=20 and C=50 cases/week. After its extra capacity becomes effective, C reaches 150 and has spare capacity 10. This is a capacity comparison, not a queue forecast or cost-effectiveness ranking.

  2. 2. State what is needed before choosing an option.

    Produce: Three missing assumptions and a robustness judgement.

    Compare your work for step 2

    Ask about duration of demand, mobilisation reliability, costs, case mix, backlog, staff welfare and acceptable waiting. C may cope with sustained high demand but expose people during the delay. B has a smaller initial gap but cannot fully meet the high case. No option is 'best' without purpose, constraints and evaluation criteria.

  3. 3. Design two parallel probes for different explanations of avoidance.

    Produce: Two small interventions with distinct hypotheses.

    Compare your work for step 3

    Probe 1 offers a choice of appointment times to a consenting small group, testing timing constraints. Probe 2 offers an optional introduction from a trusted community contact, testing a relationship hypothesis. Preserve normal support for everyone. A clearer letter could be a third probe; avoid bundling every change so that nothing can be learned about the alternatives.

  4. 4. Define sensing, dampening and amplification before acting.

    Produce: A named observer, review point and stop/adapt rules.

    Compare your work for step 4

    Review take-up, missed contact, participant experience and staff burden at an agreed short interval. Stop or alter a probe if people feel pressured, essential support is delayed or workload becomes unsafe. Expand only when evidence and context justify it, while continuing to look for harms and differences between groups.

Check the basic distinctions

These checks test the supplied case, not your overall competence. Open answers and model variants still need your judgement.

1. At high demand, what is C's initial weekly shortfall?

Answer and reasoning 1

50 cases

Only baseline capacity 90 is initially available: 140-90=50. The later 150 cannot be used before its stated delay.

2. Which is a safe-to-fail design feature?

Answer and reasoning 2

A bounded, monitored action with an available stop or adaptation route

Safety is designed through limits, sensing and response, not asserted through a label or guarantee.

Repair a defective model or claim

The plan chooses the highest eventual capacity, ignores mobilisation delay and calls a compulsory service withdrawal an experiment.
Compare your repair

Model the transition as well as the eventual state. Preserve essential support, establish consent and safeguards, and test competing explanations with bounded actions. Unknowns do not justify avoidable harm.

Try a changed case before looking

Extra capacity now takes six weeks, while high demand is expected to last four. How does that affect C?

Compare the changed case

The additional capacity would arrive after the expected surge. C's nominal peak capacity becomes less relevant to this scenario. Reconsider earlier mobilisation, another arrangement or a different hypothesis about demand; do not silently retain the original recommendation.

Review the process, not just the score

A different model can be defensible when its purpose, assumptions and reasoning are explicit. A contradiction, incorrect unit, invented fact or unacknowledged change of purpose needs repair. Keep both your first attempt and revision.

Keep your attempt

No sign-in or submission is required. Notes are not sent by this practice tool. Use fictional information, not identifiable client or learner data. Saving stores this page's attempt only in this browser; clearing browser data can remove it. Export a copy to keep it elsewhere.

External resources and their limits

The complete original case above is free. Links below distinguish exercises from explanations, recordings, software and paid study. Reading a page or drawing in a tool is not itself a model check.

Dave Snowden: coherence and uncertainty

Free | Author's explanation of safe-to-fail probes

Check whether your probes test distinct coherent possibilities and whether you have designed sensing and a response to harm.

What was checked, and what was not

Author's discussion of parallel probes, coherence, amplification and dampening inspected. This is guidance, not a complete self-marking exercise.

Research date: 2026-09-07

UK Government: introductory systems thinking toolkit

Free | Step-by-step tools, templates and examples

Select the named tool, try the associated template and compare with the example. Use the pack's explicit checks where the toolkit provides no answer key.

What was checked, and what was not

HTML toolkit inspected, including mapping, stock-flow, theory of change and evaluation sections. Its examples are not automatic validation of a learner's model.

Research date: 2026-09-07

SCiO professional development and course enquiries

Paid / enquiry | Teaching and supervised practice

Ask for practice with feedback in the named approach, rather than assuming every recording includes assessment.

What was checked, and what was not

The page lists coverage including CONAN, INFORMED and multi-methodology. Availability and individual tutor feedback require an enquiry.

Research date: 2026-09-07

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