evidence: "These conditions may be determined in proportion to hours of work, contributions or earnings." (Article 6). It extends this proportional parity in pay norm to statutory social security schemes that are based on occupational activity, "so that part-time workers enjoy conditions equivalent to those of comparable full-time workers" (Article 6). Finally, it promotes that measures be taken to ensure that part-time workers receive conditions equivalent to those of comparable full-time workers for maternity leave, paid annual leave, paid public holidays, and sick leave—provided in proportion to hours of work or earnings (Article 7). The Netherlands (where 75% of women employed work fewer than 35 hours per week) has been at the forefront of creating pro-rata equivalence for part-time workers, particularly regarding salary levels and, where reasonable, also for employee benefits (Visser et al. 2004). In the United States, San Francisco’s Formula Retail Employee Rights Ordinances have such parity for part-time workers (San Francisco Office of Labor Standards Enforcement 2020, see Section 3300G.5 ). [...] Manning, Alan, and Barbara Petrongolo. 2008. "The Part‐Time Pay Penalty for Women in Britain." Economic Journal 118, no. 526: F28–F51.