2017 Measuring Compliance 673 in fulfilling economic and social rights, (proxied by the Physical Quality of Life Index) given a country’s GDP per capita level and whether the country is a signatory and/or party to the ICESCR.66 And similarly, in the civil and political realm, Todd Landman, David Kernohan, and Anita Gohdes regress a measure of a country’s civil and political human rights performance on a number of economic, political, and social factors that are commonly understood to influence their protection. Then the residual from the regression, the unexplained variance, is used as an indicator of “over” or “under” performance with respect to the protection of those rights.67 When it comes to measuring performance with social rights standards specifically, probably the most innovative and sophisticated method that uses residual analysis for dealing with the resources dilemma to date comes in the form of the Social and Economic Rights Fulfillment Index (SERF Index), developed by Sakiko Fukuda-Parr, Terra Lawson-Remer, and Susan Randolph.68 The SERF Index measures fulfillment across five economic and social dimensions: education, food, health, housing, and decent work. For each of the dimensions, outcome indictors are selected to reflect the enjoyment in the interests to which these dimensions relate and where this enjoyment is likely to be influenced by government policy. The SERF Index attempts to deal not only with the right-holder enjoyment aspect of the task of measuring compliance but also with the duty-bearer obligation-fulfillment aspect. Specifically, the innovation in the SERF Index methodology lies in its construction of an Achievement Possibility Frontier (APF), which specifies each duty-bearer’s obligation with respect to the level of resources it has available. The feasible level of rights enjoyment is defined as the maximum level of achievement that has historically been achieved and is set simply by plotting each outcome variable against one input variable (GDP per capita, converted to 2005 international dollars using purchasing power parity (PPP) rates) across all countries for all years for which data are available over a period of roughly a decade,69 and fitting a curve to the maximum boundary observations. Then the SERF Index essentially measures the difference between the boundary, representing potential achievement, and a country’s actual achievement. That is, the residual. 66. Cingranelli & Richards, supra note 61, at 224. 67. Todd Landman, David Kernohan, & Anita Gohdes, Relativizing Human Rights, 11 J. Hum. Rts. 460 (2012). 68. Fukuda-Parr, Lawson-Remer, & Randolph, An Index of Economic and Social Rights Fulfillment: Concept and Methodology, supra note 56; Sakiko Fukuda-Parr, Terra LawsonRemer, & Susan Randolph, Economic and Social Rights Fulfillment Index: Country Scores and Rankings, (Hum. Rts. Inst., Working Paper No. 11, 2009), available at http://web2. uconn.edu/economics/working/11.pdf.; Sakiko Fukuda-Parr, Terra Lawson-Remer, & Susan Randolph, Fulfilling Social and Economic Rights (2015). 69. Fukuda-Parr, Lawson-Remer, & Randolph, Fulfilling Social and Economic Rights, supra note 68, at 41–42.