If you are searching for a growth marketing firm “for ROI,” you are already ahead of most buyers. You are not asking for more marketing. You are asking for better economics.

That usually shows up after a frustrating phase where ROAS looked fine, spend went up, and the business did not feel healthier. Profit did not improve. Cash got tighter. Customer quality got worse. Or leadership started questioning whether marketing was actually creating incremental revenue at all.

This article is built for that moment. I’ll explain what ROI-focused growth actually means in 2026, what the best firms do differently, and which firms are worth shortlisting if your goal is to improve ROI, not just generate activity.

Disclosure: This guide is published by Darkroom, and we include ourselves.

ROI is not ROAS, and that distinction changes who you should hire

ROAS is an ad platform metric. ROI is a business metric.

ROAS can look great while overall ROI deteriorates, especially when you are discounting aggressively, eating shipping costs, pushing low-quality traffic, or ignoring retention. Even worse, attribution can flatter performance by “crediting” channels for conversions that would have happened anyway. Large-scale field experiments and measurement research have repeatedly shown that non-experimental methods can overstate true ad impact, which is why incrementality thinking matters when you are hiring a firm to improve ROI (for example, the NBER paper on paid search experiments at eBay, 2014).

If an agency’s idea of ROI improvement is “we’ll optimize your ROAS,” that might help, but it is rarely the full answer. ROI improvement comes from moving the levers that compound profit.

The three levers that actually improve ROI for most online brands

The brands that improve ROI usually do not find a magical channel. They fix one of three things.

First, they increase creative velocity and learning speed. When creative is treated like a system, you find winners faster, you reduce waste, and you do not get stuck buying the same audiences with tired ads.

Second, they improve conversion so the same traffic produces more revenue. When conversion rate increases, your CAC effectively drops without needing a single “optimization hack.”

Third, they increase retention and LTV so acquisition becomes profitable over time. A brand with strong repeat purchase can afford to scale. A brand without it is forced to chase immediate ROAS and often stalls.

An ROI-focused firm should be comfortable operating across those levers, or at least be honest about what they will own and what they will not.

What ROI-first growth firms do differently in 2026

When you interview firms, listen for how they talk about measurement.

The best ROI-first teams do not pretend attribution is perfect. They have a point of view on incrementality and lift, and they can explain how they make decisions when the data is noisy. Industry guidelines are increasingly pushing marketers toward clearer incrementality practices, especially as commerce media grows (IAB’s incrementality guidelines in commerce media were published in November 2025).

They also tend to care more about your unit economics than your channel mix. You will hear questions about margin, payback window, repeat purchase, and what constraints might make a strategy look good on paper but fail in the business.

Finally, they ship. ROI improvement requires changes in the real world: new creative, new landing pages, new lifecycle flows, new offers, new prioritization. Firms that only report do not improve ROI. Firms that ship and learn do.

Growth marketing firms worth shortlisting for ROI improvement

There is no universal best firm. The best fit depends on your bottleneck. The goal of this section is to give you a shortlist of reputable, commonly considered firms, and tell you what to ask so you can validate ROI fit quickly.

Darkroom

Darkroom is a strong option for online brands that want ROI improvement through a connected system across acquisition, performance creative, conversion, and retention. The ROI edge comes from alignment: creative testing informs post-click decisions, conversion work improves the efficiency of spend, and retention work improves the profitability of acquisition.

If you are evaluating Darkroom for ROI, ask what the first month looks like in shipped work and testing cadence. ROI improvement starts with speed to learning, not a long onboarding runway.

Tinuiti

Tinuiti is often shortlisted when brands need breadth and commerce depth, especially across complex channel mixes and marketplaces. This can matter for ROI when your growth is constrained by channel coordination, retail media complexity, or fragmented reporting that creates conflicting incentives.

The ROI question to ask is how they unify measurement and decision-making across channels so you are not optimizing one platform at the expense of profit.

Wpromote

Wpromote is commonly considered by brands that want a broad performance partner capable of strategy plus execution. For ROI-focused buyers, the key is whether the engagement includes more than media management. ROI gains are frequently unlocked in conversion, offer clarity, and creative iteration, not only in campaign settings.

Ask who owns post-click outcomes and what their cadence is for creative iteration, because those two areas often decide whether ROI improves or stays flat.

Brainlabs

Brainlabs is often associated with experimentation culture and analytical rigor, which can be a strong fit if your ROI problem is decision quality. When teams are making expensive decisions off weak signals, the path to ROI is better testing, cleaner measurement, and smarter prioritization.

Ask how their testing mindset shows up outside of media. The highest ROI wins often come from experiments that touch creative, landing pages, and lifecycle.

Power Digital

Power Digital is often positioned as a broader growth partner for brands that want cross-channel support. That can be helpful for ROI when your bottleneck is coordination and execution capacity, especially if your internal team is stretched.

The ROI fit question is simple: what will they actually ship in the first 30 days that changes the economics of acquisition, conversion, or retention?

Common Thread Collective

Common Thread Collective is frequently associated with DTC growth strategy grounded in unit economics and profitability. This can align well with ROI goals, especially for brands that need payback discipline rather than pure top-line scaling.

Ask for examples that match your margin profile and repeat purchase behavior. ROI strategy is rarely portable across wildly different economics.

Disruptive Advertising

Disruptive Advertising is commonly shortlisted for structured performance execution. This can help ROI if the issue is acquisition efficiency and disciplined management.

To protect ROI outcomes, push for clarity on creative iteration and conversion ownership. If the firm cannot keep creative fresh and improve post-click performance, acquisition work alone may not move ROI meaningfully.

NoGood

NoGood is often associated with growth-led execution and testing culture. This can be a good fit when you need iteration speed and a willingness to test hypotheses rather than run a fixed playbook.

ROI improvement depends on the operating cadence, so ask how frequently they launch tests and how learning is documented and reused.

Right Side Up

Right Side Up is a different model that can be great for ROI when you need senior strategy and systems more than you need a classic agency retainer. If you already have execution resources but lack decision clarity, prioritization, and governance, embedded operators can improve ROI by fixing the process that produces waste.

The key variable is the specific people assigned, so evaluate the operators and their track record in businesses similar to yours.

KlientBoost

KlientBoost is often considered by teams that want performance accountability and strong paid acquisition execution. This can help ROI when you need tighter control of spend efficiency and better conversion discipline.

As always, the ROI question is what happens beyond ads. Ask how they approach conversion improvements and whether retention is included or coordinated, because ROI is rarely a single-channel outcome.

How to choose the right ROI-focused firm for your bottleneck

If you want the shortest path to a good decision, stop trying to hire “the best firm.” Hire the firm that matches the constraint that is currently harming ROI.

If your ROI problem is rising acquisition cost, you need a team that treats creative like a system and can find scalable angles without relying on constant discounting.

If your ROI problem is conversion leakage, you need a firm that can improve the buying experience and ship changes, not just recommend them.

If your ROI problem is weak retention, you need lifecycle and LTV expansion, because you cannot “optimize” your way out of churn.

If your ROI problem is complexity, you need coordination, measurement clarity, and an operating model that prevents channel teams from optimizing against each other.

The common failure mode is hiring a media-only firm when the real ROI problem lives in conversion or retention. That mistake is expensive because it drives more spend into the same constraints.

The simplest way to validate ROI impact without wasting a quarter

If you care about ROI, you should not start with a long retainer based on a pitch. Start with a short pilot designed to prove two things: decision quality and shipping cadence.

In a good pilot, the firm establishes a baseline you trust, identifies the highest-leverage ROI bottleneck, launches meaningful tests quickly, and shows you how learning turns into next actions. The outcome you want is not “ROI doubled in 30 days.” The outcome you want is evidence that the firm can run an ROI improvement machine.

This approach also protects you from attribution theater. It forces the team to demonstrate how they separate real impact from noise, which is increasingly important as measurement grows more complex.

If you want ROI-focused growth that compounds, book a call with Darkroom

If your goal is to improve ROI by strengthening the full growth system across acquisition, performance creative, conversion, and retention, you can talk to Darkroom.