Inputs into the model such as discounting rate and time horizon can have significant effects on the results. One controversial subject is use of a 10-year time frame to assess cost effectiveness of diabetes preventive services by the Congressional Budget Office. Preventive care services mainly focus on chronic disease. The Congressional Budget Office has provided guidance that further research is needed in the area of the economic impacts of obesity in the U.S. before the CBO can estimate budgetary consequences. A bipartisan report published in May 2015 recognizes the potential of preventive care to improve patients' health at individual and population levels while decreasing the healthcare expenditure. Economic case Mortality from modifiable risk factors Chronic diseases such as heart disease, stroke, diabetes, obesity and cancer have become the most common and costly health problems in the United States. In 2014, it was projected that by 2023 that the number of chronic disease cases would increase by 42%, resulting in $4.2 trillion in treatment and lost economic output. They are also among the top ten leading causes of mortality. Chronic diseases are driven by risk factors that are largely preventable. Sub-analysis performed on all deaths in the United States in 2000 revealed that almost half were attributed to preventable behaviors including tobacco, poor diet, physical inactivity and alcohol consumption. More recent analysis reveals that heart disease and cancer alone accounted for nearly 46% of all deaths. Modifiable risk factors are also responsible for a large morbidity burden, resulting in poor quality of life in the present and loss of future life earning years. It is further estimated that by 2023, focused efforts on the prevention and treatment of chronic disease may result in 40 million fewer chronic disease cases, potentially reducing treatment costs by $220 billion. Childhood vaccinations Childhood immunizations are largely responsible for the increase in life expectancy in the 20th century. From an economic standpoint, childhood vaccines demonstrate a very high return on investment. According to Healthy People 2020, for every birth cohort that receives the routine childhood vaccination schedule, direct health care costs are reduced by $9.9 billion and society saves $33.4 billion in indirect costs. The economic benefits of childhood vaccination extend beyond individual patients to insurance plans and vaccine manufacturers, all while improving the health of the population. Health capital theory The burden of preventable illness extends beyond the healthcare sector, incurring costs related to lost