Online Planning

There is another way to act well without solving the whole enormous problem: don't. Just work out the best move from where you actually are, right now.

Chapters 6 and 7 computed a policy offline — a complete rule worked out in advance, covering every state. Online planning takes the opposite stance. It computes nothing ahead of time; instead, whenever a decision is due, it looks ahead from the current state, evaluates the plausible futures, picks the best immediate action, takes it, then repeats the whole exercise from the new state. It spends effort at decision time rather than storing a policy — and for project work, it mirrors how good practitioners actually think.

1Look ahead, act, repeat

The simplest form is receding-horizon planning: look ahead a fixed number of steps, choose the best first move as if the world ended at that horizon, then slide the horizon forward and redo it after each step. You never commit to the distant future — you only ever commit to the next action, and you recompute constantly as reality unfolds. This is rolling-wave planning in everything but name.

Figure 1. Online planning builds a shallow tree of futures from the current state, backs up estimated values, and commits only to the best next action. After acting, it discards the tree and plans afresh from wherever the project now stands.

2Searching futures cleverly

The art is in exploring possible futures without drowning in them. Forward search expands the tree of actions and outcomes to a set depth. Branch and bound prunes branches that provably can't beat the best found so far. Sparse sampling keeps the tree manageable by sampling a limited number of outcomes per action. And the standout, Monte Carlo tree search, grows the tree selectively toward the most promising lines: it repeatedly selects a path (balancing promising moves against under-explored ones), simulates a rollout to the end, and backs the result up the tree. It concentrates effort where it matters and has powered some of the strongest game-playing systems ever built.

Key idea

Online planning refuses to solve the whole problem and instead solves the only part that's due: the next move. It trades a stored policy for fresh computation at each step — and re-plans continuously as the project reveals itself.

What it means in practice

You do not need a pre-baked answer for every situation a project could reach — you need the best next decision from the situation you're in, and the discipline to recompute it as things change. Simulating a few moves ahead from the current state, then committing only to the immediate action, is rolling-wave planning made rigorous. Look ahead far enough to see the consequences that matter, act, and plan again from where you land.

Handbook application: from concept to controlled practice

Purpose. This expanded section turns the original page into a practical handbook. It preserves the supplied material and adds a repeatable way to apply, check and review Online Planning. It does not replace a contract, legislation, a controlled standard, competent engineering judgement or specialist advice.

The operating aim is to convert the subject into a governed decision, owned work, usable evidence and a reviewable outcome. Read the original explanation first, then use the workflow and checks below to convert knowledge into evidence.

Use Online Planning as a decision instrument rather than an administrative form. The subject terms—search, online, planning, ahead, forward—need an explicit connection to the project objective, business value and stakeholder commitments. Before completing the artefact, write one sentence stating who will use it, what decision it supports and when that decision is required.

Apply a disciplined information model. Separate facts supported by evidence, forecasts derived from a method, assumptions awaiting validation, constraints that limit choice, risks that may occur, issues that already exist and actions assigned to people. Each material entry should have an owner, date, status and next review point. Where probability or impact scores are used, define the scale so different reviewers interpret it consistently.

A baseline is useful only when changes are visible. Give the artefact an identifier, version, approval state and effective date. Define which changes require reapproval, how superseded versions are retained and where supporting evidence is stored. During reviews, focus on exceptions, decisions and trends rather than reading every field aloud. Record the decision and rationale, not merely that a meeting occurred.

Close the loop beyond delivery. Confirm acceptance criteria, unresolved items, transferred responsibilities and operational ownership. Where benefits are expected, identify the outcome measure, baseline, target, observation period and owner who remains accountable after the project team disbands. Lessons should describe the condition, consequence and reusable action; a generic statement such as “communicate better” cannot improve the next project.

Step-by-step operating method

Clarify the decision. Name the outcome, sponsor, affected stakeholders and decision that this work must enable.
Set boundaries. Record scope, assumptions, constraints, dependencies, tolerances and escalation conditions.
Plan the evidence. Define deliverables, measures, owners, due dates and acceptance criteria before execution.
Control delivery. Compare actual performance with the baseline, assess changes and manage risks and issues explicitly.
Close the loop. Confirm acceptance, transfer ownership, capture lessons and track benefits beyond handover.

Completion and governance protocol

Start with a short drafting workshop involving the accountable owner and the people who hold the evidence. Complete high-consequence fields first: objective, scope, owner, baseline, acceptance, dependencies and escalation. Mark unknowns as assumptions or actions rather than hiding them behind vague prose. Circulate a review draft, resolve conflicting interpretations, baseline the approved version and place the next review date in an owned schedule.

Information type	Minimum useful content	Review test
Outcome	Observable change and intended recipient	Not merely a deliverable or activity
Measure	Definition, baseline, target, frequency and source	Two reviewers would calculate it the same way
Ownership	One accountable role plus contributors and approver	Authority matches responsibility
Uncertainty	Assumption, risk or issue with response and trigger	Status reflects current reality
Control	Version, approval, review date and change rule	Current baseline is identifiable

Common failure modes and recovery actions

1. Watch for

Producing a document with no named decision or accountable owner.

Recovery: Return to the governing definition or requirement and restate the decision in one sentence.

2. Watch for

Mixing risks, current issues, assumptions and actions in one unstructured list.

Recovery: Separate evidence from assumption, assign an owner and set a date for validation.

3. Watch for

Measuring activity or output while leaving the intended outcome undefined.

Recovery: Run a small counterexample, boundary test, pilot or independent check before proceeding.

4. Watch for

Accepting changes without evaluating effects on value, scope, schedule, cost and risk.

Recovery: Record the consequence, decision and rationale, then update the controlled baseline.

5. Watch for

Closing the project at delivery even though benefit ownership has not transferred.

Recovery: Escalate when the issue affects safety, compliance, acceptance, material value or an agreed tolerance.