> ## Documentation Index
> Fetch the complete documentation index at: https://planmyrounds.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Roster constraints and scheduling rules

> A reference for the work-pattern, rest, and fairness rules the PlanMyRounds scheduling engine applies when generating a duty roster for your clinical team.

When PlanMyRounds generates a roster, it applies a set of **hard** and **soft** rules to produce a schedule that is both valid and fair. Some rules you set yourself in the [creation wizard](/docs/rosters/creating-a-roster); others are applied automatically based on doctor profiles and approved leave.

This page is a reference for every rule the engine respects.

## Hard vs. soft constraints

* **Hard constraints** must be satisfied. If the engine cannot meet them, generation fails.
* **Soft constraints** are preferences. The engine tries to honour them but may bend them if there's no other way to produce a valid schedule.

## Work and rest rules

Set per roster in **Step 4** of the creation wizard. All of these are **hard** constraints.

| Rule                                    | What it does                                                                                           |
| --------------------------------------- | ------------------------------------------------------------------------------------------------------ |
| **Max consecutive work days**           | A doctor cannot work more than this many days in a row without a day off.                              |
| **Min rest days per week**              | Every doctor must have at least this many days off in every seven-day window.                          |
| **Min rest hours between shifts**       | Always enforced. No two shifts assigned to one doctor can be closer than this many hours apart.        |
| **Recovery after 1 shift**              | Minimum rest required after any single shift.                                                          |
| **Recovery after 2 consecutive shifts** | Applies when **back-to-back duties** are enabled. A longer rest is required after two shifts in a row. |

## Approved leave

[Approved leave](/docs/leave/approval-workflow) entries are **hard** constraints. The engine will never assign a doctor to a shift on a date they have approved leave for.

[Shifts to avoid](/docs/leave/applying-for-leave#mark-shifts-to-avoid) are **soft** constraints. The engine tries to honour the preference, but if there's no other option the doctor may still be assigned.

<Note>
  Only **Approved** leave is applied. Pending or rejected requests have no effect on generation. Always clear your pending queue before generating a roster.
</Note>

## Senior-to-junior ratio

For organisations on the advanced scheduling engine, each shift can require a defined ratio of senior to junior doctors — for example, *one senior for every three juniors*. This is a **hard** constraint.

## Shift-specific staffing requirements

Each shift template defines:

* **Required doctors** — the exact headcount per occurrence.
* **Min seniors required** — the minimum number of seniors per occurrence.

Both are **hard** constraints. If you don't have enough doctors to meet these across the full period, generation will fail.

## New doctor onboarding period

If configured, doctors who joined within a defined number of days can be protected from specific shift types during their onboarding period. This is set at the roster level under **Other Configurations**.

Use this to ease new joiners in gradually — for example, no night shifts in their first 30 days.

## When generation fails

<Warning>
  If the engine cannot find a valid schedule that satisfies every hard constraint, the roster shows a **Failed** status. The reason will appear on the roster page.
</Warning>

Common fixes:

* **Add more doctors** to the team so the engine has more options.
* **Loosen a rule** — for example, raise max consecutive work days or lower the minimum rest days.
* **Approve outstanding leave** before retrying so the engine has a complete picture.
* **Shorten the period** if the date range was very long.

## Next steps

<CardGroup cols={2}>
  <Card title="Create a roster" icon="wand-magic-sparkles" href="/docs/rosters/creating-a-roster">
    Apply these rules in the four-step wizard.
  </Card>

  <Card title="Roster and shift statuses" icon="signal" href="/docs/rosters/statuses">
    Reference for every status you'll see on a roster.
  </Card>
</CardGroup>