When teams discuss fraud prevention, block rate is often one of the first numbers they consider.
It’s easy to understand. It’s easy to compare. And it appears to provide a clear measure of how actively an anti-fraud service is working.
But block rate alone cannot tell you whether the right decisions were made.
A high rate may indicate that an anti-fraud tool is successfully identifying a serious fraud problem. It may also mean that legitimate customers are being stopped unnecessarily. For a content service provider or payment aggregator, that can affect conversion and revenue. For a mobile operator, a high rate may raise questions about traffic quality and whether a service – or even a market – is sustainable.
A low block rate can be equally difficult to interpret. It may reflect clean traffic and effective controls earlier in the customer journey. Or it may mean that suspicious activity is not being detected.
The number needs context.
The goal of fraud prevention should therefore be neither to maximise nor minimise blocking. It should be to take proportionate action against genuine risk while supporting legitimate customers and sustainable mobile-payment revenue.
A block is an action, not a business outcome
Blocking a transaction tells us that an intervention took place. It doesn’t tell us whether the intervention was correct.
To understand that, teams need to ask:
- What activity was detected?
- Why was it considered suspicious?
- Which parts of the customer journey contributed to the decision?
- Was the activity genuinely harmful?
- Could legitimate customers have been affected?
- What happened after the intervention?
Without these answers, a block is simply an event in a report.
This can create tension between teams. Fraud specialists may see risk that requires action. Commercial teams may see falling conversion. Customer service teams may see an increase in complaints. An operator may see evidence of poor-quality traffic.
Each team sees a different part of the picture. Effective fraud prevention helps them understand the same evidence and reach a better-informed decision.
Fraud has a wider commercial impact
The direct financial value of fraudulent transactions that result in customer complaints and refund requests is important, but it is not the only cost businesses should consider.
Fraud can also lead to:
- Increased customer service workloads
- Disputes between commercial partners
- Greater scrutiny from operators and regulators
- Loss of confidence in a traffic source or service
- Restrictions on carrier billing activity
- Damage to consumer trust
- Lost opportunities to enter or grow in a market
Poorly judged fraud controls can create their own costs. If controls are too aggressive, genuine customers may be prevented from completing a purchase. This makes it challenging for everybody in the value chain to hit targets and remain profitable. If controls are too weak, harmful activity may continue until complaints or partner concerns force a much wider response.
The challenge is not simply to stop fraud. It is to intervene accurately enough to protect the long-term health of the service and the wider value chain.
Commercial pressure makes the decision harder
Mobile-payment businesses operate in a competitive environment. Traffic volumes, conversion rates and revenue targets matter.
This can create pressure to reduce blocking when transaction volumes are affected. At the same time, fraud and compliance teams may face pressure to show that strong controls are in place.
Neither pressure should decide the outcome on its own.
Weakening controls to preserve short-term revenue can allow customer harm and complaints to grow. Increasing blocking without examining the evidence can reject genuine customers and make an otherwise viable service appear unhealthy.
The right response must be based on the nature of the activity, the strength of the evidence and the likely effect on customers and partners.
This is why fraud prevention is not only a technical function. It is a business discipline that connects risk, customer experience, operations and commercial performance.
From a fraud signal to a defensible decision
A useful anti-fraud process should automatically move activity through a clear, evidence-led workflow, while giving teams the visibility and control to review decisions when needed.
1. Flagged
Potentially suspicious activity is identified within the customer journey.
A flag should begin an investigation. It should not automatically be treated as proof of fraud.
2. Investigated
The platform automatically analyses what happened, where the activity came from and which indicators contributed to the alert.
This helps distinguish genuine risk from unusual but legitimate customer behaviour. Where further review is needed, teams have the evidence to examine the activity without starting the investigation from scratch.
3. Explained
The reasoning behind the decision is made clear to the people who need it.
This may include fraud specialists, account managers, commercial teams, operators or other partners. A decision is more valuable when it can be explained without requiring specialist technical knowledge.
4. Actioned
The business takes a proportionate next step.
That may mean blocking newly suspicious activity out of caution, monitoring an emerging pattern, investigating a source or refining future decision logic.
This process turns fraud signals into clear, defensible business decisions.
What should businesses measure?
There is no single measure of effective fraud prevention. The right combination will depend on the service, market, customer journey and organisation’s risk appetite.
A more complete assessment could include:
- Complaints, refunds and customer support contacts
- Longer-term customer and revenue performance
- Are all the partners in the value chain algined
- Confirmed fraudulent activity identified or prevented
- Legitimate conversion retained
- Time required to investigate an alert
- Decisions that can be traced to clear evidence
- Traffic quality by source, campaign or market
- Partner queries and disputed decisions
- The effect of changing a rule or threshold
Businesses do not need to measure everything at once. They do, however, need enough evidence to understand whether their controls are producing the intended result.
A useful starting point is to agree what a good outcome means for each stakeholder. Fraud, commercial, operational and customer teams may use different measures, but they should be able to connect them.
Five questions to start the conversation
Businesses reviewing their current approach can begin with five practical questions:
- Can we clearly explain why particular activity was blocked?
- Do we know whether legitimate customers are being affected by our controls?
- Can we assess how changing a rule might affect both fraud risk and conversion?
- Can we explain a disputed decision to a customer, operator or commercial partner?
- Are our fraud and commercial teams working from the same evidence?
If these questions are difficult to answer, the problem may not be the block rate itself. The business may need clearer evidence, better investigation tools or a more connected decision-making process.
Building a more connected approach
At MCP Insight, we analyse more than 450 million customer journeys every month for indicators of fraud. This scale has reinforced an important lesson: the value is not simply in detecting more fraud signals. It is in helping businesses understand which signals matter and what action should follow.
Our updated anti-fraud solution – MCP SHIELD – is designed around clearer evidence, faster investigation and more proportionate decisions. The objective is straightforward: deliver safe revenue, keep the industry on a strong footing, block high-risk transactions, investigate suspicious behaviour, and turn fraud signals into clear, defensible business decisions.
Continue the conversation in Marbella
At World Telemedia Marbella, we will be discussing how businesses can reduce fraud without creating unnecessary barriers for legitimate customers or undermining sustainable mobile-payment growth.
Meet MCP Insight at World Telemedia Marbella, 4-6 October 2026, to explore what a more proportionate, explainable and business-focused approach could look like for your organisation.
Smarter fraud prevention. Better business outcomes.
Book a meeting with MCP Insight in Marbella
