Ninsiima (Siima) Rukandema, from Hookflash, believes that the most expensive things in marketing right now aren’t your media budget – but the decisions you make without testing it first.
Below, she examines how to validate marketing impact in a controlled, valuable way.
A client recently launched a full website redesign. No prior testing, multiple changes introduced simultaneously. Post-launch, the overall conversion rate was down 14%, PDP conversion dropped 21%, PLP conversion dropped 34% – and because everything went live at once, it was impossible to isolate the cause or find a clear path to fix it.
A painful pill to swallow and a heavy cost as a result of untested change.
Marketing spend is under scrutiny like never before – 57% of UK companies have flatlined budgets, with the remainder split between cuts and increases.
Yet, under that same scrutiny, organisations continue to make big bets on new website features, redesigns and campaigns based on opinion rather than evidence, while simultaneously investing in driving more traffic to sites that aren’t actually converting.
With less discretionary expenditure available, experimentation is severely misunderstood as a nice-to-have and we are seeing a fundamental contradiction come to life: organisations are becoming more cautious with spend but not necessarily more effective with the decisions that assess and determine whether that spend works.
Experimentation: the gift that keeps on givingÂ
Experimentation works in this gap. Unlike traditional CRO, which focuses narrowly on conversion rate improvements through tactical tweaks like button colours and checkout flows, experimentation applies the same testing methodology to the full range of business decisions.
Not just how to optimise a page, but whether to redesign it, to invest in a new platform or to launch a new feature.
The question shifts from “how do we improve conversion rate?” to “how do we make better decisions about everything that affects whether our marketing works?”
That distinction matters when budgets are tight and while CRO is easy to cut; a framework that prevents expensive mistakes is considerably harder to argue against.
What’s more, the value is not only in the uplift but in the learning as these insights don’t sit in isolation – they can be applied across channels, ensuring user insight informs not only your website but your broader marketing strategy.
Before committing budget to a new feature or redesign, experimentation allows teams to validate impact in a controlled way. In one case, we worked with a brand that was continuously redesigning elements over a three-month period.
Testing revealed that, despite the team feeling confident, some of those changes were actually detrimental and responded to poorly by users. We saved them £120,000 in investment by catching changes they would otherwise have rolled out at scale. In this case, not optimisation but prevention.
Experimentation also works as a budget efficiency multiplier, optimising the performance of already existing traffic rather than requiring additional spend. An events client was driving significant volumes of paid search traffic to their homepage but there was a disconnect between the ad messaging and the landing page content
Users were clicking through on one promise and arriving at something that didn’t match. We tested aligning the messaging across the journey, matching the landing page to what users had seen in the ad. The consistency drove a 132% uplift in conversion rate for that PPC audience without any additional budget required.Â
Ultimately, experimentation’s greatest strength is enabling teams to root their decisions in evidence rather than guesswork. A client was considering investing in the review platform, Bazaarvoice.
Rather than committing upfront, we tested the impact of surfacing reviews on key pages first and saw that it drove a 54% uplift in conversion. This gave the team a clear cost-benefit analysis, a commercial justification for the investment and confidence that the change genuinely improved user experience, rather than just acting as a vanity metric.
Optimisation tactics
It exemplifies the role of experimentation as a decision-making tool rather than just an optimisation tactic.Â
In a climate where every budget decision is scrutinised, the organisations that pull ahead will not be the ones that spend more carefully. They will be the ones that decide more carefully where to spend, rooting changes in evidence rather than opinion, testing before committing and treating experimentation not as a discretionary line item but as a framework that makes every other investment more likely to work.
The most expensive decisions in marketing are not the ones with the biggest price tags but the ones that don’t deliver results.