---
title: Planning a project and measuring time spent
description: Scheduling on the Gantt chart, chaining tasks, freezing a planning baseline, estimating effort and logging time.
url: "http://illizeo.com/en/centre-aide/projects-planning-and-tracking-time/"
updated: "2026-11-11"
category: Core HR services / HR project management
---

# Planning a project and measuring time spent

Planning a project means dating its tasks, chaining them and setting its milestones; measuring means comparing what was planned with what is happening: dates against a frozen baseline, estimated effort against the time actually spent. This article explains the **Gantt** view, dependencies between tasks, planning milestones, planning baselines, estimated effort and logging time. It is aimed at project leads and members of project teams.

## Before you start

- The Gantt view is part of the **Tasks** tab: you need the **Project task** permission at the Access level to read it, and at the Execute level with a role that writes in the project (**Project manager** or **Developer**) to reschedule.
- Freezing, activating or deleting a planning baseline is reserved for the project manager and cross-project managers.
- Logging time on a task requires the Attendance module to be installed and the right to fill in your own timesheet. You can only log time for yourself.
- Billing milestones appear on the Gantt chart with the **Billing milestones — Manage** permission at the Access level.

## The Gantt view

1. Open the project, **Tasks** tab, then click **Gantt**.
2. Choose the **Scale**: **Day**, **Week**, **Month** or **Quarter**. A vertical line marks **Today**.

![Gantt view of the project Refonte de l’intranet at the Week scale: tasks grouped by sub-project (Cadrage, Déploiement, Réalisation), the Mise en ligne milestone marked with a diamond, the task bars on the November and December timeline, the arrow linking Annuaire des collaborateurs to Portail documentaire, the red line for today and the Billing row; at the top, the Day, Week, Month, Quarter choice and the Baseline : Plan validé au cadrage button, with its panel open: the active baseline, the Name of the new baseline field and the Freeze the schedule button.](https://i0.wp.com/illizeo.com/wp-content/uploads/2026/11/projets-10.en_.png?resize=800%2C540&quality=80&ssl=1)
The Gantt chart groups tasks by sub-project; the baselines panel opens above it.

Tasks are grouped by sub-project; those without one are grouped under **No sub-project**. Undated tasks are kept apart, under **Unscheduled**. A **Billing** row shows the billing milestones, read-only; a paid milestone is marked “paid”. Click a bar to open the task form.

### Rescheduling by dragging

- Drag a bar to move it: its start and due date move together.
- Drag its right edge to change only the due date.
- Drag an unscheduled task onto the timeline to date it on the chosen day.

Without write access, the Gantt chart shows “Read only.” and can only be viewed.

## Chaining tasks: dependencies

A dependency says that a task can start only after another has finished (finish-to-start link). You create one in two ways:

- on the Gantt chart, drag the dot at the end of a bar onto the task that must wait;
- in the form of the waiting task, **Depends on** section, click **Add a preceding task…**, search for the task and pick it.

The form also lists the tasks waiting for it, under **Awaited by**. To remove a link, click its arrow on the Gantt chart, or the cross next to the preceding task in the form. A link that would close a loop is refused.

### What Illizeo reschedules for you

- A task starts at the earliest on the day after each of its preceding tasks ends. If placed too early, it is moved back; a message says so.
- If a preceding task finishes later, its following tasks are pushed by as much as needed, in cascade, keeping their duration. The message “Following task moved” (or “N following tasks moved”) names them.
- If it finishes earlier, the following tasks do not move back: slack appears.
- A completed or cancelled task never moves, and the cascade stops there. A task without dates is neither constrained nor moved.

On the Gantt chart, a red arrow flags a following task that starts before its preceding task ends.

## Planning milestones

A planning milestone marks a key step on a single date: a go-live, a steering committee, a delivery. To create one, tick **Planning milestone** in a task form and enter the **Milestone date**. On the Gantt chart, it is a purple diamond, green once reached, red if its date has passed without it being reached; it can be dragged like a task. On the Kanban board, its card is labelled “Milestone”.

A planning milestone is unrelated to a billing milestone, which carries an amount and is managed in the [project Settings](https://illizeo.com/en/centre-aide/projects-settings-and-finances/).

## Freezing the schedule: baselines

A planning baseline takes a snapshot of all task dates at a given moment, for example when the scoping is approved. From then on, the Gantt chart, the list and the Overview measure slippage against it.

1. In the Gantt view, click the baseline button (**No baseline**, or **Baseline :** followed by the name of the active baseline).
2. Enter the **Name of the new baseline**, for example “Scope approved”.
3. Click **Freeze the schedule**. The new baseline becomes the active baseline.

You can keep several baselines. In the panel, **Compare** makes another baseline active; the bin icon deletes one. The panel reminds you that the Gantt chart and the list compare due dates to the active baseline.

### Reading the variances

- In the **List**, the **Variance** column gives each due date’s slippage in days; “not in baseline” marks a task added after the baseline.
- On the **Gantt** chart, a task added since is flagged “Added after the active baseline”.
- In the **Overview**, the **Planning baseline** card compares the planned end with the baseline end and counts the tasks and milestones late against it (see [Monitoring a project from the Overview](https://illizeo.com/en/centre-aide/projects-overview-tab/)).

## Estimating effort

Each task can carry an **Estimated effort**. It is entered in the project’s unit, set in Settings, Finances card, **Task effort estimates** section: **Hours** or **Days**, with the length of a day (**One day =**, 8 hours by default). Changing the unit does not distort any total: Illizeo keeps estimates in hours.

A task’s **Remaining work** is calculated by Illizeo: the estimate minus the time already logged, never negative, and zero for a completed or cancelled task. In the form, you can correct it by entering a value; clearing the field goes back to the calculation. Added to actual time, it gives the **At completion** projection in the Overview’s Workload card.

## Measuring time spent

A task’s actual time is the time members have allocated to it, whether entered or clocked in their timesheet. In the task form, the **Time** section compares it with the estimate and lists who logged time, on which day, how much, and on which sub-task.

### Logging time from the task

1. Open the task form and click **Log time**.
2. Choose the **Day**.
3. Depending on your attendance profile that day, enter the **Start** and **End** times, or a **Duration**.
4. Choose the **Sub-task** if needed and add a **Comment (optional)**.
5. Click **Log**.

![Form of the task Annuaire des collaborateurs: the Depends on section (no preceding task, awaited by Portail documentaire), the Time section (0 h of 80 h estimated, 80 h left) and the Log time form with the reminder about the timesheet, the Day, Start and End, the sub-task choice, the Comment (optional) and the Cancel and Log buttons.](https://i0.wp.com/illizeo.com/wp-content/uploads/2026/11/projets-12.en_.png?resize=624%2C380&quality=80&ssl=1)
Time logged on a task goes to your timesheet.

Your time goes to your timesheet, pending approval, under the same rules as an entry made from the timesheet. If your profile plans nothing that day, the form shows “No attendance profile on that day.”; if the day counts as a flat day, “This day counts as a flat day: no hours to log.”. For entries in the timesheet itself, see [Filling in and submitting your timesheet](https://illizeo.com/en/centre-aide/attendance-timesheet/).

## Good to know

- Only an active member of a project with the Active status can log time against it.
- Time logged on a sub-task counts towards its task’s actual time.
- Dependencies link tasks within the same project.
- Taking a baseline, activating another or deleting one is traced in the project’s recent activity.

## Frequently asked questions

### I moved a task and others moved too. Why?

They depend on the task you moved: Illizeo pushes them so that they start after it ends. The message shown after saving names them.

### I can’t see the Freeze the schedule button.

It is reserved for the project manager and cross-project managers. Other members can see the baselines but not create them.

### The Log time button does not appear.

The Attendance module is not installed, or your role does not let you fill in your timesheet.

### *Similaire*