In this chapter is a review of the methodology for the construction of the summary measures of population health (SMPH): Disability-Adjusted Life Year (DALY) and Health-Adjusted Life Expectancy (HALE). In order to better understand GBD’s SMPH, this chapter compared DALY and HALE with two other similar SMPH, Healthy Life Expectancy (HLE) and Quality-Adjusted Life Years (QALY). The methodology for constructing GBD’ SMPH is at the heart of the Global Burden of Disease (GBD) study. This chapter consists of five sections: Sect. 2.1 introduced the development history of SMPH and some important SMPHs; Sect. 2.2 introduced the common methods and GBD’ method of the measurement of health status; Sect. 2.3 introduced the common and GBD’s valuation methods of disability weight; Sect. 2.4 introduced the methods for calculation of DALY and HALE; and Sect. 2.5 summarized the strengths and weaknesses of HALE and DALY. Important points in this chapter include understanding the categorization of SMPH. DALY is seen as a health gap metrics, and HALE is seen as a health expectancy metrics. The second point is how to calculate life-years lost (YLL), and selecting the standard reference life table for YLL. The third point is how to calculate the years of disability life-years lost (YLD), including the mapping of the sequelae to the health states, the health state disability weights establishment, establishment of health state severity distributions, microsimulation methods for comorbidity adjustment. The last point is how to calculate DALY and HALE. The underlying element of DALY and HALE, YLD, is constructed as disease prevalence weighted by the common values formed by public perceptions of how much health loss there is for each health state and is not related at all to disability status in the population. In addition, it is emphasized that DALY does not measure disability in the population and there is no comparison at all between DALY and HALE and other SMPHs such as QALY.