Based on the contributions of Stiglitz et al. (2009) the Social Progress Index (SPI), a comprehensive measure of a country’s performance, was created. This paper proposes an alternative form of calculation and analyzes the relationship of the index with variables such as GDP or other measures of subjective well-being. The main results indicate that the new method of calculation provides more homogeneous results in terms of the classification of countries, compared to the original index. Thus, middle-income countries are the most susceptible to change, and the opportunities dimension is the one that would require special attention due to its low score and potential for improvement. Moreover, this dimension, together with GDP, has a statistically significant relationship with happiness (considered as a proxy for subjective well-being).