# Feature OP-14235 - Add visual baseline comparison for Gantt chart

Project: OpenProject
Status: new
URL: https://community.openproject.org/work_packages/OP-14235

## Planning

| Attribute | Value |
| --- | --- |
| Date |  |
| Priority | Medium |
| Target versions | Wish List |
| Sprint |  |
| Backlog bucket |  |
| Votes | 8 |
| List |  |
| Roadmap |  |
| Relevance |  |

## OPEN POINTS / FEEDBACK

_No work packages_

## Features and Chunks

_No work packages_

## Bugs and other work packages

_No work packages_

## Technical Details

| Attribute | Value |
| --- | --- |
| Module |  |
| Feature Flag |  |
| Requires doc change | Yes |
| Enterprise plan |  |

## Details

| Attribute | Value |
| --- | --- |
| Pull preview |  |
| Mockups |  |
| Found in mobile app version |  |
| Follow-up feedback e-mail |  |
| Accessibility | No |

## People

| Attribute | Value |
| --- | --- |
| Assignee |  |
| Accountable |  |
| Product manager |  |
| Developers |  |
| Designer |  |
| Ordered by |  |
| Signed off by |  |
| Interest by |  |

## Estimates and progress

| Attribute | Value |
| --- | --- |
| PD (min) |  |
| PD (max) |  |
| Work |  |
| Labor costs |  |

## Description

**User story**  
As a project member  
I want a visual baseline comparison of the Gantt chart  
so that I understand how my team performed against the initial time estimation

**Acceptance criteria**

  - I can compare the Gantt chart of a project by setting two dates (baseline comparison)

  - It visualizes the changes that have been made since the baseline date

**Original user question:**  
"Is there a way to compare the Gantt chart of a project at different points in time? I would like to see how it changes over time for certain projects and understand how did we perform the initial time estimation."

\----------

Requested in <mention class="mention" data-id="77323" data-type="work_package" data-text="#SPAR-285" data-display-id="SPAR-285">\#SPAR-285</mention> as well, here is the copy of its description:

**As a project manager** using baselines to track progress and deviations, I want to see one or more selected baselines rendered as additional bars directly in the Gantt chart, so that I can identify schedule deviations (ahead of / behind plan) at a glance without opening the work package list details.

**Acceptance criteria**

  - In the Gantt view, the user can activate a baseline overlay via the existing baseline selection.

  - For each work package, the baseline is displayed as a second bar next to (e.g. below) the current work package bar.

  - The overlay also applies to milestones (and phases), so that milestone shifts against the baseline are visible directly in the chart.

  - The user can freely choose which baseline to display (e.g. "yesterday", "last working day", a specific date, or a saved baseline).

  - It is possible to display and compare multiple baselines simultaneously (e.g. Baseline 1 and Baseline 2 next to the current bar). When multiple baselines are shown, there is a clear arrangement (stacking order, row height) and visual distinction between them (e.g. different grey shades plus a legend), so that a trend across several baseline dates remains recognizable at a glance.

  - The baseline bar(s) are styled in grey and/or semi-transparent to be clearly distinguishable from the current (colored) plan bar.

  - Each baseline bar is positioned exactly at its original start and finish date; the current bar remains unchanged.

  - Deviations are immediately recognizable: if the current bar starts/ends earlier or later than the baseline bar, this is visible without any additional interaction.

  - The direction of the deviation (ahead of / behind plan) is visually indicated (e.g. via color coding or a delta connector between the baseline finish and the current finish), and the deviation in days is shown in the bar's tooltip.

  - The overlay works consistently with existing Gantt features (zoom levels, collapsing/expanding, filtering).

  - Work packages without baseline values (e.g. created after the baseline date) show no baseline bar.

**Technical notes**

  - Reference for expected UX: Jira Advanced Roadmaps baseline display (screenshot see activity tab).

**Permissions and visibility considerations**

  - To whom is this feature visible?
    
      - To all users who have permission to view the Gantt chart / work packages of the project; the baseline overlay follows the same visibility rules as the existing baseline function in the work package table.

  - When is it not visible?
    
      - When no baseline is selected/activated, when the user lacks permission to view the work packages, or for work packages that have no data for the selected baseline date.

**Translation considerations**

  - Key terms and phrases in the key languages
    
      - "Show baseline in Gantt chart" (EN) / "Baseline im Gantt-Diagramm anzeigen" (DE)
    
      - Tooltip labels such as "Original start date" / "Ursprüngliches Startdatum" and "Original finish date" / "Ursprüngliches Enddatum"
    
      - Deviation labels such as "Deviation" / "Abweichung", "ahead of plan" / "vor Plan" and "behind plan" / "hinter Plan"

**Out of scope**

  - Changes to the existing baseline display in the work package list/table.

  - Automatic scheduling or re-planning based on baseline deviations.

  - Baseline variance reports/exports (numeric deviation reports beyond the visual overlay); the in-bar tooltip deviation in days is part of the visual overlay and not considered a separate report.

  - Editing or moving the baseline bars (baselines remain read-only).