One of the questions a planner is asked most often is “what changed between this revision and the last one.” LogicReader answers it directly: load both versions, click Compare, and read the diff on a single canvas.
Step-by-step
- Load the older revision first — Load XER or Load CSV.
- Click Add Project in the toolbar (not Load — Load replaces, Add appends).
- Select the newer revision file. Both projects now appear in the Projects panel on the left.
- Click Compare. A panel appears asking which project is the baseline (older) and which is the comparison (newer).
- The canvas updates with the diff overlay applied.
Reading the diff
- Green fill — activity is new in the newer revision.
- Red fill with a strike-through — activity was removed.
- Amber fill — activity exists in both revisions but at least one tracked attribute changed (dates, duration, name, calendar, predecessors).
- Green dependency arrow — the link is new.
- Red dashed dependency arrow — the link was removed.
- Solid blue arrow — the link is unchanged.
Activities that are identical in both revisions render in their normal colour with no badge.
Inspecting a specific change
Click any amber activity to open the inspector panel. It lists every changed attribute, baseline value on the left, comparison value on the right, with the delta highlighted. For changed dates, we also show the calendar-aware day count between baseline and comparison.
Narrowing the diff
If the schedule is large and the diff is busy, combine Compare with Isolate: select the WBS branch you actually care about, isolate it, and the comparison overlay only shows for the visible nodes. Everything else drops out of the canvas, and your meeting becomes about one scope, not the whole programme.
What Compare does not do (today)
- It does not produce a written variation report. You can screenshot the canvas; a one-click meeting pack export is on the roadmap.
- It does not currently group changes by who made them — ownership of the change comes with the typed-dependency work that is also on the roadmap.
- It does not merge revisions. There is no “accept this change” button. The diff is read-only.
A note on identifiers
Compare matches activities across revisions by their identifier. With XER input, that’s the unique task_id — rock solid. With CSV input, it’s the composite of project_id and task_code. If activities have been renumbered between revisions (rare but it happens), they will appear as one removal and one addition, not as a change. There is no good way around this: if the planner has changed the activity’s identifier, the tool has no way to know it is the same activity.