The idea would be to allow users to enter data such as Journey investment/cost, number of customers impacted, conversion rate, average order value, and revenue generated, and have the system automatically calculate the ROI. In addition to revenue generated, I’d also like to consider cost avoidance for Journeys that don’t necessarily generate revenue but help reduce or avoid costs. What other inputs, metrics, and formulas would you consider important to make this calculation more reliable, especially when it comes to incremental revenue, cost avoidance, and control groups ?
#Marketing Cloud #Marketing Cloud Engagement #Tactics Driving Marketing ROI #Journey Builder
Lukas Lunow (NoA Ignite) 
Forum Ambassador
Good question, and one I'd like to answer properly, but the honest answer is that the shape of what you build changes completely depending on a few things you haven't told us yet. So let me ask rather than guess.
First, a snag in the input list. You've got conversion rate, AOV and revenue generated as separate inputs. Those can't all be independent, either revenue is derived (contacts × CR × AOV) or it's measured from actual order data. If both, the calculator can disagree with itself on day one. Which is it meant to be?
Is this a forecast or a scorecard? A pre-launch business case with sliders and ranges, and a post-launch "what did this actually earn us" report, are two different artefacts. Same formulas, completely different data sources and completely different build. Most of these tools get abandoned because they try to be both.
Are your journeys always-on or campaign-shaped? For an always-on journey, ROI isn't a number, it's a curve. Contacts keep entering, conversion rate drifts, build cost is sunk and shrinking per contact over time. You'd need entry cohorts and a payback view, not a single figure.
Do you already have holdouts running? This is the big one. Without a control group you're not measuring incremental anything, and no amount of formula design fixes that. If you do have them: are they persisted per contact, or re-rolled with Random Split on each entry? And is there a global holdout as well as per-journey ones? (Per-journey lifts don't sum to portfolio lift, and the gap matters.)
Where do revenue and cost data actually live? MCE has neither revenue nor margin nor cost of goods. That pushes the actuals half of this toward Data 360 / your warehouse / Tableau, with MCE contributing engagement and holdout membership. Is that available to you, or are you constrained to build inside MCE?
Who owns the cost-avoidance assumptions? Cost avoidance is where business cases go to get manufactured. If Finance hasn't signed off on "cost per deflected call," it's a soft number and should be flagged as one.
One last thing, said kindly: most of this question isn't really MCE-specific. Incrementality design, control-group methodology, margin vs revenue, cost-avoidance taxonomy: that's marketing measurement, and it would be true if you were running Braze or a spreadsheet. The genuinely MCE-shaped slice is narrow: how to persist a holdout flag so it survives re-entry, how to get engagement data out into something that can join it to orders, and whether a Cloud Page + assumptions DE is a sane place to put the front end. Happy to go deep on that slice here, since that's what this group is good at.
For the measurement-design half you'll get better answers where the analytics and architecture folks hang out. The Marketing Architects group, or a Data 360 / Tableau group. Genuinely worth cross-posting; it's a good question, just a two-venue one.
Tell me which of these apply and I'll happily go into the formulas with you.