The first column is a decomposition of the formal-informal wage differential that seeks to prove the null hypothesis of equation (2), namely that earnings are significantly higher for formal than for informal workers. The mean predictor of the natural log of hourly wages is 1.05 pesos for informal workers and 1.48 pesos for formal workers, yielding a negative and significant difference of -0.43. When the Blinder-Oaxaca decomposition is carried out, both parts are significant: 67% is explained by differences in personal, job or sectoral characteristics, while 33% is unexplained and could be considered evidence of labour market segmentation. It] is particularly problematic if certain attributes of occupations are included as ‘explained factors’ in this first component, like industry, for example, because this implicitly assumes that segregation is due to the voluntary decisions of men and women” (Bergmann, 2004, quoted in Esquivel, 2009, p. 18).