In 2024, Kenya introduced its Social Health Insurance Act, which caught the attention of data scientists across Africa. The country implemented a sophisticated means-testing tool to evaluate citizens’ capacity to afford health insurance. What sets this tool apart is that it is not intended for everyone. Let me elaborate on why this is particularly intriguing.
The Tale of Two Systems
Picture Jane, a bank manager in Nairobi, and Mohammed, a fruit vendor in Mombasa. Their paths to health insurance couldn’t be more different. Jane’s contribution is straightforward – her employer automatically deducts 2.75% from her monthly salary. For Mohammed, however, determining a fair contribution requires a more nuanced approach. This is where the means-testing tool comes into play.
The tool’s primary target is Kenya’s vast informal sector – the Mohammeds of Kenya, comprising nearly 83% of the workforce. These are the small business owners, market vendors, farmers, and craftspeople whose incomes fluctuate monthly and who often operate outside traditional banking systems.
Breaking Down the Mathematics
The heart of this means-testing tool lies in a logarithmic regression model that, at first glance, might seem intimidating:

Let’s unpack this equation through real-world scenarios.
The Urban-Rural Divide
That small ‘u’ superscript throughout the equation? It’s crucial. According to Kenya’s 2019 census, approximately 31.2% of Kenyans live in urban areas, while 68.8% reside in rural regions. But it’s not just about population distribution but fundamentally different economic realities.
Consider two farmers: One in rural Nyeri selling coffee beans, and another in peri-urban Kiambu supplying vegetables to Nairobi’s restaurants. Despite similar occupations, their income potential, market access, and economic opportunities differ vastly. The means-testing tool accounts for these variations through location-specific calibrations.
Structural Parameters (aᵘ)
The structural parameter ‘a’ might include:
- Regional economic indicators (GDP per capita in different counties)
- Local healthcare facility density
- Distance to major economic centres
- Market access indices
- Infrastructure development levels
For instance, a vendor in Nairobi’s CBD faces different structural economic conditions than one in rural Turkana, and the model accounts for these variations.
Household Indicators (bᵘXhᵘ)
The household component may consider factors like:
- Asset ownership (land, livestock, vehicles)
- Housing conditions (rental vs owned, construction materials)
- Utility access (electricity, water, internet)
- Number of dependents
- Educational investments
Take Sarah, a single mother in Kisumu running a small shop. Her household indicators would factor in not just her business income, but also her housing situation, whether she owns the shop premises, and how many children she’s supporting through school.
Individual Factors (cᵘZhiᵘ)
Individual-specific indicators might include:
- Education level
- Skills and certifications
- Business type and scale
- Years in current occupation
- Banking history
- Mobile money transaction patterns
For example, a skilled carpenter in Nakuru who maintains regular M-PESA transactions might have a different assessment than a seasonal agricultural worker with irregular income patterns.
The Data Science Challenge
We’ve developed Python and PHP implementations of this means-testing tool, and the testing process has revealed fascinating challenges. How do you verify self-reported income in a cash economy? Can mobile money transactions serve as a proxy for income stability? Should the model weight education differently in areas with limited employment opportunities?
Real-world Applications
Let’s look at how the means-testing tool might assess three different cases:
- A motorcycle (boda boda) rider in Eldoret:
- Regular but variable daily income
- Owns his motorcycle
- Rents a single room
- Supports two children
- A market vendor in Mombasa:
- Seasonal income fluctuations
- Rents a market stall
- Owns a small plot upcountry
- Has three dependents
- A small-scale farmer in Kakamega:
- Harvest-dependent income
- Owns land and livestock
- Limited formal banking history
- Large family size
Each case requires different weighting of factors and demonstrates why a one-size-fits-all approach wouldn’t work.
Looking Forward
The success of this means-testing tool could revolutionize how developing nations approach universal health coverage. It’s not just about collecting contributions – it’s about creating a fair, sustainable system that acknowledges economic realities while ensuring healthcare access for all.
As we continue testing our implementations, we’re discovering that the real power of this model lies in its adaptability. The parameters can be fine-tuned based on regional differences, economic changes, and emerging patterns in the informal sector.
Technical Implementation Notes
For fellow data scientists interested in similar implementations, we’ve developed both Python and PHP versions of this means-testing tool. Our code repositories include comprehensive documentation and test cases based on simulated data from various economic scenarios. The implementations feature robust error handling, configurable parameters, and integration capabilities with existing government systems.
Conclusion
The means-testing tool in Kenya is more than just a mathematical model; it’s a step towards addressing one of the most persistent challenges in healthcare: how to accurately assess the ability to pay in informal economies. As we gather more data and refine the model, we are witnessing the potential development of a blueprint for healthcare financing in developing nations.