Development and construction of synthetic indicators for socioeconomics inevitably face the very same concern confronting many quality of life (QOL) measures for individuals: how to account for potential societal, cultural and individual differences in values associated with different sectors, facets or domains represented by different indicators. In QOL research, a common approach is to use weighting to reflect the potential individual differences in values associated with different facets or domains of life. Also known as importance weighting in QOL literature, researchers capture individual differences in values, using relative importance of different facets or domains of life with the assignment of weights. Although using importance weighting to capture relative importance of various life facets or life domains appears straightforward, there are a number of conceptual and methodological issues that remain unsettled. In this chapter, major issues related importance weighting in QOL measures are discussed to provide implications for developing and constructing synthetic indicators.