Potential Biases in The Immunization Program Evaluation

The Ventura County Public Health Immunization Program is aimed at benefiting different groups of people, such as pregnant women, children, lactating mothers, and school students through vaccines. When assessing the immunization program, the evaluation design may be faced with potential bias. Selection bias is the first problem likely to happen due to the loss of some data. There are lots of activities and services offered through the program. The bias threatens the validity of the program. Attrition happens, where a group of people or some individuals who started the immunization decide to drop out (Crowcroft & Klein, 2018). Some of the participants, such as pregnant or lactating women, may not be willing to give out personal information. Differential attrition will be experienced since I will not assume that the immunization of pregnant women had the same outcome as lactating mothers. Lack of participation will affect the result of the evaluation. Therefore, the information may not reflect the effectiveness of the immunization program.   

Secular trends in Ventura County may cause bias in the evaluation process. When there is an event at the county, some people will not attend the center for immunization. Therefore, data will be disrupted, and that will affect the results. The evaluation process may also be influenced by beliefs related to the adverse effects of some vaccines given to children, such as hepatitis scare (Crowcroft & Klein, 2018). Such cases will reduce the number of women willing to take their children to the medical center for immunization. The trends of the external resources such as the CDC vaccines and immunization information and California Hepatitis prevention programs may keep on changing, thus affecting effective data collection and creating trends of the immunization program. The maturation also influencing effective evaluation due to the implementation of health practice programs among adults. These biases can be addressed by changing the evaluation designs and choosing a practical approach, such as quasi-experimental design.    

Reference 

Crowcroft, N. S., & Klein, N. P. (2018). A framework for research on vaccine effectiveness.  Vaccine .