HLTH 3115 Week 2 Measurement Exercise Example

Building Kenya's 2016 Tuberculosis Notification Rate: The Division, the Five Choices Behind It and What the Finished Figure Cannot Answer

Student Name

Walden University

HLTH 3115: Public and Global Health

Instructor Name

Month Day, Year

Building Kenya's 2016 Tuberculosis Notification Rate: The Division, the Five Choices Behind It and What the Finished Figure Cannot Answer

The Question

How many tuberculosis cases did Kenya's health system notify in 2016, relative to the size of the population? The answer is a notification rate: the number of cases reported to the national tuberculosis program in a year, divided by the population at risk, multiplied by 100,000. This exercise builds that rate from published figures, states each choice made along the way and explains what the finished figure can and cannot tell a reader.

The Numerator

Kenya's national tuberculosis program notified 77,376 cases in 2016, according to the report of the country's 2016 prevalence survey (Enos et al., 2018). The same report notes that this figure was about 46% of the estimated 169,000 people who fell ill with tuberculosis in Kenya that year.

Choice 1: what counts as a case. A notified case is one that was diagnosed and reported to the program. It includes all forms of tuberculosis, pulmonary and extrapulmonary, and all ages. It is not a count of everyone who had tuberculosis; it is a count of everyone the system found and recorded.

Choice 2: which year. The numerator is the calendar year 2016, chosen because the prevalence survey report gives that year's notifications and because it allows comparison with the survey's own estimates for the same year.

The Denominator

Choice 3: which population estimate. Kenya's population in 2016 can be taken from more than one source. The World Bank's indicator series, built on United Nations population estimates, gives 48,139,687 for 2016 (World Bank, 2026a). Kenya's own 2019 census counted 47,564,296 people three years later (Kenya National Bureau of Statistics, 2019). For 2019 itself, the international series gives 51,202,827, about 3.6 million more than the census counted (World Bank, 2026a). The two sources disagree by millions of people for the same year. For this exercise, the World Bank figure is used, because it gives a value for the exact year and is the series the international tuberculosis estimates rely on. The choice is stated so a reader can recompute with another denominator.

Choice 4: which population. The denominator is the whole population, all ages, to match a numerator that includes all ages. Using adults only would require removing child cases from the numerator, which the published total does not allow.

Choice 5: crude, not adjusted. The rate is crude. It is not adjusted for age, so it reflects Kenya's actual age structure, in which about 42% of people were under 15 in 2016 (World Bank, 2026b). Comparing it with a rate from a country with an older population would require age adjustment.

The Division

Kenya's 2016 tuberculosis notification rate was about 161 per 100,000 people. Put plainly, for every 100,000 people in Kenya, the national program diagnosed and recorded about 161 cases of tuberculosis that year.

Table 1

Kenya Tuberculosis Notification Rate, 2016

Using Kenya's 2019 census count as the denominator instead would raise the rate to about 162.7 per 100,000, a small change but one a careful reader should be able to see.

Checking the Figure

The rate can be checked against other published figures. The prevalence survey report gives the WHO incidence estimate for Kenya in 2016 as 348 per 100,000, revised upward after the survey (Enos et al., 2018). The notification rate of 161 is a little under half of that, which matches the report's statement that about 46% of people who fell ill were notified. The two figures are consistent, which suggests the arithmetic and the denominator choice are reasonable.

Why Each Choice Matters

Each of the five choices could reasonably have gone another way, and each would change the figure or its meaning. Counting only bacteriologically confirmed pulmonary cases would lower the numerator and make the rate comparable with the prevalence survey, which measured only that form. Using a different year would change both numerator and denominator, and in 2017 notifications may have risen as programs responded to the survey's findings. Using the census-based denominator raises the rate slightly, as the table note shows. Restricting to adults would make the figure match the survey's population but would require case counts by age that the published total does not provide. Age adjustment would allow comparison with other countries but would produce a figure that describes no real population. Declaring the choices lets a reader see which version of the rate they are looking at and recompute it if they need another.

What the Figure Cannot Answer

The notification rate answers one question: how many cases the system recorded, relative to the population. It cannot answer several others.

It cannot say how many people had tuberculosis. Notifications count only cases that were diagnosed and reported. Among adults, the survey's ratio of existing to notified cases was 2.5 to 1, and fewer than half of the people it diagnosed had the persistent cough that usually leads to a test (Enos et al., 2018). A low notification rate could mean little disease or a system that misses many cases.

It cannot say whether tuberculosis is rising or falling. A rise in notifications could reflect more disease or better case finding. In the year after a prevalence survey and new diagnostic tests, notifications can rise simply because the system is looking harder.

It cannot say who is affected. A single national rate hides the survey's finding that men, adults aged 25 to 34 and urban residents carry more disease. A rate by sex, age or region would be needed.

It cannot be compared directly with other countries without adjustment. Kenya's young population means a crude rate may look different from that of a country with more older adults, even if age-specific risks were similar.

Conclusion

The division is simple: 77,376 notified cases divided by 48,139,687 people, multiplied by 100,000, gives about 161 per 100,000. The work lies in the five choices behind it, each of which a reader could make differently, and in the paragraph that explains what the number measures: the system's recorded cases, not the country's disease.

References

Enos, M., Sitienei, J., Ong'ang'o, J., Mungai, B., Kamene, M., Wambugu, J., Kipruto, H., Manduku, V., Mburu, J., Nyaboke, D., Ngari, F., Omesa, E., Omale, N., Mwirigi, N., Okallo, G., Njoroge, J., Githiomi, M., Mwangi, M., Kirathe, D., ... Weyenga, H. (2018). Kenya tuberculosis prevalence survey 2016: Challenges and opportunities of ending TB in Kenya. PLoS One, 13(12), Article e0209098. https://doi.org/10.1371/journal.pone.0209098

Kenya National Bureau of Statistics. (2019). 2019 Kenya population and housing census: Volume I. Population by county and sub-county. Kenya National Bureau of Statistics.

World Bank. (2026a). Population, total, Kenya (Indicator SP.POP.TOTL) [Data set]. World Development Indicators. https://data.worldbank.org/indicator/SP.POP.TOTL?locations=KE

World Bank. (2026b). Population ages 0-14 (% of total population), Kenya (Indicator SP.POP.0014.TO.ZS) [Data set]. World Development Indicators. https://data.worldbank.org/indicator/SP.POP.0014.TO.ZS?locations=KE