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Data Cleaning for MMM: The Foundation of Accurate Marketing Insights

6 min read
Written by: Scott Zakrajsek
Scott Zakrajsek Head of Data Intelligence

Scott Zakrajsek is a data-driven marketing executive with over 15 years of experience leading digital transformation for iconic brands. As Head of Data Intelligence at fusepoint and Power Digital, he specializes in turning complex data ecosystems into actionable strategies that drive growth.

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Marketing Mix Modeling (MMM) is becoming one of the most reliable ways to understand the incremental impact of every marketing channel, but MMM only works when the underlying data cleaning process is strong. 

Open-source tools like Robyn, Meridian, and PyMC make modeling accessible, yet many marketers still struggle to get accurate results because the raw data feeding the model hasn’t been cleansed, validated, or structured consistently. Even advanced models can’t overcome dirty data, missing data, or inconsistent data types. Clean data—properly scrubbed, standardized, and documented—is what makes MMM trustworthy.

What You Need Before Running an MMM

Before building any model, you need a dataset that is complete, consistent, and structured the same way across platforms. MMM depends on:

  • Two to three years of daily media spend across all paid channels

  • Conversion data such as revenue, leads, transactions, or sign-ups

  • External factors including promotions, holidays, seasonality, product launches, and macro trends

These inputs become the foundation of your dataset. If the raw data isn’t aligned—wrong formats, duplicate data, incomplete exports, or mismatched definitions—your model will pick up noise instead of signal. Effective MMM starts with strong data management and a repeatable cleaning process.

The Most Common Data Quality Problems

The most common challenges stem from data quality issues that appear small but compound quickly. Missing data is the biggest culprit: platform migrations with no backups, offline buys tracked informally, unreported spend, or data locked behind expired agency logins. Even one missing month can affect model accuracy. 

Another barrier is inconsistent structure. Campaign naming conventions rarely match across teams, conversion definitions change over time, branded and non-branded search are blended together, and different platforms export different data types or date formats. These inconsistencies require data scrubbing, data transformation, and careful validation to produce a clean dataset. 

Access issues also slow down MMM readiness. When logins are scattered, multiple owners manage different parts of the data, or historical exports are lost, you end up with fragmented information that can’t be stitched into a unified dataset. Without centralized data access and accountability, data quality issues compound.

Why Data Cleaning Matters More Than Model Complexity

Many marketers overestimate the importance of model complexity and underestimate the importance of data cleansing. The truth is simple: a basic model fed clean data will produce better insights than a complex model fed dirty data or incomplete data. 

Data accuracy, data consistency, and data fluency matter more than Bayesian settings or algorithm selection. When the data cleaning process is strong, MMM becomes far more reliable and easier to refresh, audit, and explain to stakeholders.

Essential Data Cleaning Techniques for MMM

A structured, repeatable cleaning process is what makes MMM scalable. Key best practices include:

  • Centralizing all data sources so every dataset, KPI, and access owner is documented

  • Standardizing definitions for conversions, revenue logic, funnel stages, naming conventions, and attribution windows

  • Running regular data validation checks to catch duplicates, outliers, mismatched date ranges, missing fields, and inconsistent labeling

  • Tracking external events such as promotions, pricing changes, launches, and supply shifts so the model can separate real marketing lift from unrelated spikes

  • Automating data collection through ETL pipelines or scheduled exports to reduce manual errors and improve long-term data quality

  • Assigning clear data ownership so every data source stays clean, updated, and accessible
    These steps help maintain a clean dataset, reduce inconsistent data, and ensure the model has the high-quality data it needs to perform.

Real-World Impact

For one client, simply cleaning inconsistent naming, recovering missing data, validating historical exports, and splitting blended search channels increased model fit by 30%. Once the dataset was cleansed and validated, the model finally had the structure it needed to surface clear, defensible recommendations and reveal the real incremental drivers of growth.

Data Cleaning Best Practices for Data Science & Data Analytics

MMM works when the data behind it is clean, structured, and complete. Strong data cleaning protocols transform scattered, raw data into a reliable dataset that supports confident forecasting and smarter budget decisions. Whether you need to handle missing data, a data quality issue, irrelevant data, data visualization, or another form of data analysis, fusepoint has data infrastructure solutions to help.

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