Incidence refers to the number of new cases of a disease that develop in a population during a specific time period. It does not account for existing cases.

Mortality rate is a measure of the number of deaths in a population, typically in a specific time period. It is not specific to the disease being studied.

Survival rate is the proportion of people in a study or treatment group who are alive for a certain period of time after diagnosis. It does not reflect the total number of disease cases in a population.

Prevalence refers to the total number of people in a population who have a disease at a given time, irrespective of when they first developed the disease. High prevalence means that a larger proportion of the population is affected with the disease. The researcher's findings therefore indicate a higher prevalence of spinal bifida in this population.