Did you know that a project can be full of hardworking students and still be late because everyone began the tasks in the wrong order? A group might decorate a display board before its facts are checked, print captions before agreeing on their wording or rehearse a presentation that has not yet been assembled. Working faster on the wrong step does not remove the wait created by unfinished prerequisites.
Quick answer: a task dependency is a relationship in which one activity needs an earlier activity to begin or finish first. Plan a project by identifying what each task needs as input, who can work in parallel, and what must be checked before the next hand-off. A good schedule follows those dependencies, makes the next verifiable action obvious and leaves room to correct mistakes without pretending they were never made.
- Describe a concrete finished product and the criteria it must meet.
- Break the work into tasks with a visible completion condition.
- Record which earlier tasks each task depends upon.
- Place independent tasks side by side only when people and equipment are available.
- Calculate when the last dependent task can actually finish.
- Review delays against the sequence, not only against a list of effort or enthusiasm.
Diagnose the first mistake: which task may start now?
Imagine four students preparing a school exhibition about how to read maps. Their tasks include choosing a question, gathering reliable examples, checking explanations, designing a display and rehearsing a talk. One student proposes beginning with the colourful border because it is enjoyable and easy to finish. Another suggests checking the definitions first so the border will surround accurate content.
Neither creativity nor decoration is the enemy. The issue is sequence. The border can be designed independently if dimensions and layout are settled, but final captions should not be printed before they are checked. A productive diagnostic question is: “If we finish this task today, will someone else have the information needed for the next task tomorrow?” A finished border may help the display; it does not by itself unlock source checking.
A dependency is different from a priority
Priority expresses importance or urgency. Dependency expresses logical order. Verifying a map scale may be important; printing a poster may be urgent because the printer is available for only one session. But printing the final scale explanation before verifying it can create rework. These are three separate considerations: importance, prerequisites and resources.
The simplest dependency is “finish A before starting B.” In more complex work, two tasks can begin together, one task can start after another begins, or two teams must both finish before assembly. For a school project, ordinary finish-before-start rules are a helpful first model. Project Management Institute material on critical-path scheduling uses activity relationships to describe precisely this ordering principle. The classroom version should remain understandable without specialist software.
Fully worked example: plan six project sessions
This is an illustrative invented schedule, not an account of a real school’s assessed project. Assume the group has one work session per numbered day, all tasks require whole sessions, and separate team members are available to complete two independent tasks simultaneously. These assumptions matter: without parallel capacity, the schedule would be different.
The project contains six tasks. A: agree on the central question (1 session). B: gather and annotate sources (2 sessions, after A). C: design the board layout (2 sessions, after A). D: fact-check final explanations (1 session, after B). E: assemble the final board (1 session, after both C and D). F: rehearse with the completed board (1 session, after E).
Start with A in session 1. Once A finishes, B and C can run in parallel in sessions 2 and 3, provided different students can do the work. B then unlocks D, so the content-checking session is session 4. By the end of session 4, C and D are both complete. E can therefore occur in session 5, and F in session 6. The earliest completion is the end of session 6 under the stated assumptions.
The two branches are easy to compare. The route A → B → D → E → F takes 1 + 2 + 1 + 1 + 1 = 6 sessions. The route A → C → E → F takes 1 + 2 + 1 + 1 = 5 sessions. Because the branches can run in parallel and assembly waits for both, the longer branch determines the earliest completion. This is the practical idea behind a critical path.
Check the arithmetic with a delay
Suppose B unexpectedly needs an extra session. Then B occupies sessions 2, 3 and 4. D must move to session 5, even though C finished at the end of session 3. E shifts to session 6 and F to session 7. The project now finishes after 7 sessions, not 6. Ask pupils which fact explains the delay: the source-gathering task now controls when the fact-check can start.
Next suppose C, instead, needs one extra session, ending at session 4 rather than 3. D still finishes at the end of session 4, so E can still start in session 5. Under these assumptions, the overall completion stays at session 6. This does not make design unimportant; it shows that different delays have different effects depending on the dependencies and available spare time.
Do not add every task duration as though no parallel work were possible: 1 + 2 + 2 + 1 + 1 + 1 = 8 task-sessions of effort is not the same as 6 elapsed project sessions when two of those tasks overlap. Conversely, do not promise a six-session finish if the same lone pupil must perform both B and C. The model requires separate capacity during sessions 2 and 3.
Make the task list usable rather than decorative
Write each task on one card with four fields: output, predecessor, owner and evidence of completion. The B card might say “three annotated source examples; after A; research pair; links, dates and short notes checked.” The D card might say “reviewed explanations; after B; reviewer; every claim matched to its source.” For a simple school exercise, the evidence need not be elaborate; it must be observable.
An arrow from B to D means D cannot be completed responsibly without B’s output. An arrow from both C and D to E means the board cannot be assembled until its layout and content are both ready. If a learner draws an arrow that serves no clear purpose, ask whether it is a genuine necessity or merely a preference. Unnecessary arrows can make a plan slower than it needs to be.
Progression: help first, then remove the scaffolds
Guided level: identify one prerequisite
Give “write the final caption” and “verify the correct scale on the map.” Which should finish first? For this invented project, the scale must be checked before the final caption claiming it is accurate is approved. A draft caption may be written earlier and marked provisional. A careful learner can distinguish a draft from a checked final product.
Supported level: fill a three-task chain
Present “collect photographs → choose which photographs illustrate the claim → write captions that accurately describe them.” Ask the learner to write which output travels from each task to the next. Then ask what happens if the chosen photograph lacks the feature the caption claims. The caption must be changed or the photograph replaced; cosmetic formatting will not fix the evidence gap.
Independent level: a new four-task timetable
Suppose G lasts 1 session and starts first; H and I each last 2 sessions and both begin after G; J lasts 1 session and needs H and I finished. With separate students available for H and I, G occupies session 1, H and I occupy sessions 2 and 3, and J occupies session 4. The earliest completion is 4 sessions, not 6. Require students to draw the arrows and show the schedule, not just announce four.
Transfer level: find the hidden resource conflict
Now tell the learner that one student must do both H and I. Under the simple rule that the student cannot perform two full-session tasks at the same time, those four task-sessions become sequential after G. J follows them, so the earliest completion becomes 6 sessions: one for G, four for H and I, one for J. This is an example of how available people can change a technically correct dependency schedule.
What should a parent or teacher check?
A parent can ask, “What is waiting for what?” rather than “Why haven’t you finished?” A child may be blocked by a missing file, an unanswered question or a genuine decision that has not been agreed. The useful next step might be clarifying the dependency rather than working later into the evening.
A teacher can review the task cards in a five-minute meeting: what finished, what evidence proves it, what task is unlocked and which blocker needs assistance? This encourages students to state a specific request for help. If the group says, “The teacher has not approved the source list,” the next action is to request or complete that review, not to report the final references as approved.
Progress is visible when learners can identify a dependency without prompting, revise a schedule after one delay, and distinguish effort from elapsed time. Comparing an initial plan with a corrected plan tells more about growing planning skill than awarding praise for a visually polished chart alone.
Limits: real schedules are less tidy
School days include absences, shared printers, teacher reviews and variable amounts of work. Tasks may take fractions of a session, some overlap is possible and some activity durations are uncertain. The worked example deliberately uses whole sessions and simple finish-to-start dependencies to make the logic transparent. It is not a promise that every project can be scheduled with exactly six sessions.
A group should also avoid inventing progress to satisfy its schedule. “Submitted for approval” and “approved” are different statuses. “Source located” and “claim verified” are different tasks. If a deadline is immovable, adjust scope or request help early rather than quietly skipping a required check.
FAQs
Can two tasks ever be done at the same time?
Yes, if neither depends on the other at that stage and the necessary people, tools and space are available. Parallel work is a choice supported by conditions, not merely by enthusiasm.
Does the longest task always cause the final delay?
No. The sequence of dependent tasks matters. A short review on the controlling path can delay the whole project, while a longer independent design task may have room to finish without moving the deadline.
What if an earlier task is technically finished but contains errors?
If the next task requires its accuracy, the predecessor is not ready for that hand-off. Record the repair openly and update the schedule rather than concealing unfinished work.
How do we avoid making the plan too complicated?
Start with a small number of meaningful deliverables, genuine dependency arrows and clear evidence of completion. Add detail only where it helps the team make a decision.
Keep the reasoning connected to the work
Read how to record project decisions without turning suggestions into agreements and how to schedule work when groups need the same equipment. The eduKate Education Hub connects this practical work with wider learning. The Secondary 1 Mathematics Clementi reference demonstrates why progressive explanation, practice and independent checks are useful beyond any one subject.
The aim of a schedule is not to prove that everyone is busy. It is to make the next sensible action visible and protect the quality checks that turn many separate tasks into one reliable finished result.