Since the entry into force of Royal Decree 902/2020 on pay equality between women and men, companies with 50 or more employees are required to draw up a pay equity audit integrated into their equality plan. Many organisations face this process with doubts about what data to collect, how to calculate the indicators and, above all, what to do when the numbers confirm that a gap exists. This article explains, step by step, how to conduct a rigorous pay equity audit, what information the regulation requires and how to turn findings into real corrective measures.
What is a pay equity audit and what does Spanish law require?
A pay equity audit is the systematic analysis of a company's salary structure with the aim of detecting whether there are differences in remuneration between positions of equal value held by women and men, and of identifying their causes. It is not an accounting review: it is an equity diagnosis.
Royal Decree 902/2020, published in the Official State Gazette on 14 October 2020 and in force since 14 April 2021, requires companies with an equality plan to include a pay equity audit in it. The threshold of 50 employees is calculated on the average workforce of the previous year. The audit must be renewed every four years, coinciding with the validity of the equality plan, or sooner if there are substantial changes to the pay structure.
In addition, RD 902/2020 requires all companies, regardless of size, to maintain a pay register broken down by sex, occupational group, category and position. This register is the starting point for any audit.
Phase 1: collection and organisation of salary data
Before calculating any indicator, you need to build the pay database. The minimum fields it must contain are:
- Anonymised identifier for each person (not the name, to comply with GDPR).
- Sex as recorded on payroll.
- Occupational group and pay level according to collective agreement or internal structure.
- Category or job position.
- Contract type (permanent, temporary, part-time) and working hours as a percentage.
- Seniority in the company and in the position.
- Annual gross fixed remuneration.
- All supplements: shift allowance, night work, hazard pay, collective agreement bonus, merit, targets, on-call, availability.
- Variable pay and commissions, averaged over the last 12 months.
- Benefits in kind at assessed value.
- Overtime paid.
A frequent mistake is working only with the base salary and ignoring supplements. The gender pay gap in Spain is often found precisely in discretionary supplements — availability bonuses, commissions, management supplements — where the assessor's subjectivity can introduce bias. According to the Annual Wage Structure Survey of the National Statistics Institute (2023 data, published in 2025), the unadjusted gender pay gap in Spain stands at around 15–16% in favour of men (15.7% in the 2023 figure), but when variables such as sector, working hours and occupation are controlled, the adjusted gap is substantially lower according to academic research; that residual difference is what the pay equity audit must explain and, if it has no objective justification, correct.
Phase 2: job evaluation
The most technically demanding part of the audit is job evaluation. RD 902/2020 explicitly prohibits evaluation systems that, although apparently neutral, produce discriminatory results on grounds of sex. Evaluation factors must be applied consistently to predominantly female and predominantly male positions.
Analytical evaluation systems consider four broad groups of factors:
- Skills and knowledge: formal education, required experience, technical and relational skills.
- Effort: physical, mental and emotional. A classic mistake is scoring physical effort — often associated with male-dominated positions — more highly than emotional or relational effort, which is frequent in care, assistance or customer-facing roles with a female majority.
- Responsibility: over people, financial resources, materials and quality.
- Working conditions: physical environment, risks, atypical hours.
The result of the evaluation is a weighted score for each position. Positions with similar scores are of «equal value» for the purposes of RD 902/2020 and must therefore have equivalent remuneration regardless of who holds them.
Phase 3: calculation of gap indicators
With the data organised and the positions evaluated, the indicators are calculated. Spanish regulations do not impose a single formula, but established practice and the technical guide of the Women's Institute recommend the following:
| Indicator | Simplified formula | Alert threshold |
|---|---|---|
| Unadjusted gender pay gap (GPG) | (Average male salary − Average female salary) / Average male salary × 100 | Above 5% across the whole workforce |
| Gap adjusted by occupational group | Difference in means within each group, controlling for hours | Differences > 3% within the same group |
| Gap in supplements | Ratio of female supplements / male supplements | Ratio < 0.95 |
| Gap in variable pay and commissions | Difference in average variable pay, controlling for assigned targets | Difference > 5% with no documented objective cause |
| Vertical segregation index | % women in management positions / % women in total workforce | Value < 0.70 indicates a glass ceiling |
| Part-time gap | % women part-time vs % men part-time | Difference > 15 percentage points |
The analysis must be carried out by segment: the overall average is not enough. A company can have zero gap on average and a significant gap in technical positions or at management level. Breaking the data down by business unit, workplace and occupational group is essential.
Phase 4: identification of causes
When a statistically relevant gap is detected, the audit must investigate its causes. The most frequent ones in Spanish SMEs are:
- Occupational segregation: concentration of women in positions with lower collectively agreed pay.
- Discretionary supplements without written criteria: availability or versatility bonuses assigned without a documented protocol.
- Differences in access to variable pay: less ambitious targets or unequal commercial resources for female-dominated teams.
- Impact of leave of absence and reduced working hours for childcare, which fall predominantly on women and affect seniority and career progression.
- Differentiated starting salary bands in individual hiring negotiations, a bias that accumulates throughout working life.
Investigating the causes requires reviewing works council minutes, internal promotion criteria, performance appraisals and selection processes from the last four years. It is also advisable to conduct qualitative interviews with HR managers and workers' representatives, whose participation is mandatory in the equality plan negotiation process.
Phase 5: corrective measures and action plan
Detecting a gap without corrective measures does not comply with the regulation. RD 902/2020 requires the audit to include an action programme with measurable objectives, responsible parties, timelines and monitoring mechanisms. The most common measures are:
- Review and rebalancing of salary bands by occupational group.
- Establishment of objective, written criteria for the assignment of discretionary supplements.
- A salary negotiation protocol for hiring that prevents the initial offer from varying based on the candidate's sex.
- Career development plan for predominantly female positions that currently have little representation at higher levels.
- Review of the target-setting system so that it reflects the real conditions of each team.
- Work-life balance measures that reduce the impact of leave of absence on salary progression.
Measures must be prioritised according to the size of the gap detected and the organisation's financial capacity. The aim is not to level all salaries at once — that would create viability problems for SMEs — but to eliminate differences without objective justification and set a realistic timeline to reduce those that do have a cause but which the company wishes to correct.
If your company needs support in designing and implementing these measures, the equality plans service at Summum Consultoría offers accompaniment from the initial negotiation through to registration in the REGCON, including the pay equity audit as part of the process.
Phase 6: registration, communication and monitoring
Once the measures have been approved with the legal representatives of the workers, the pay equity audit and the equality plan must be registered in the REGCON (Register and deposit of collective agreements, collective work agreements and equality plans), accessible through the Ministry of Labour. Failing to register exposes the company to sanctions that, under the LISOS, can reach 225,018 euros in the most serious cases.
Monitoring must be annual: review the indicators, document the evolution of the gap and update the measures if the results are not progressing as planned. After four years, a new full audit is carried out.
Internal transparency also matters: communicating to the workforce the main results of the audit — without identifying individuals — and the measures adopted reinforces the credibility of the process and reduces labour disputes.
Common mistakes that invalidate the audit
At Summum Consultoría, with more than 15 years of experience in business consultancy for SMEs and mid-market companies, we regularly identify these mistakes in pay equity audits:
- Using only the base salary and ignoring supplements. The real gap is usually in variable pay.
- Comparing only identical positions, not positions of equal value. The regulation requires comparing any position with an equivalent evaluation, even if the content is different.
- Not involving the legal representatives of the workers. The negotiation process is mandatory and its absence invalidates the plan.
- Confusing the pay gap with discrimination. There are admitted objective causes (seniority, documented performance, market rates for scarce profiles). What the law prohibits is a difference without objective and justified cause.
- Not updating the pay register annually. The register must reflect data for the current year, not the year of the last audit.
Frequently asked questions
Are companies with fewer than 50 employees required to conduct a pay equity audit?
Not directly, but they must maintain a pay register broken down by sex. Companies with fewer than 50 employees are not required to have an equality plan — and therefore no pay equity audit either — unless their collective agreement expressly requires it or the Labour Inspectorate requires it in the context of an investigation into possible discrimination. Nevertheless, carrying out a voluntary pay analysis is good practice and can prevent future labour disputes.
What happens if the audit detects a pay gap? Do salaries have to be increased immediately?
Not necessarily immediately. The regulation requires eliminating differences without objective justification and drawing up a corrective plan with a timeline. Differences that do have an objective cause (proven seniority, documented performance appraisal, market scarcity for a specific profile) are admissible if they are properly justified in writing. What is not acceptable is maintaining a gap with no documented explanation. The corrective plan can spread the salary adjustments over the period of validity of the equality plan — up to four years — provided the pace of correction is realistic and verifiable.
Who can conduct the pay equity audit: internal HR or an external consultancy?
It can be carried out by internal HR staff if they have the necessary technical knowledge in job evaluation and statistics. However, companies that opt for an external consultancy specialising in equality plans gain several advantages: greater objectivity — especially when there is a conflict between management and workers' representatives —, proven methodologies and technical support in the event of an inspection. In any case, the negotiation process with the legal representatives of the workers is always mandatory, regardless of who carries out the analysis.
Is the pay equity audit the same as the equality plan?
No, they are two distinct instruments, although they are linked. The equality plan is the strategic document that captures the company's diagnosis across multiple dimensions (recruitment, training, promotion, work-life balance, pay, harassment prevention…) and the measures to correct the inequalities identified. The pay equity audit is the specific analysis of the pay gap and is a mandatory part of the equality plan for companies with 50 or more employees. A pay register can exist without an equality plan (in companies with fewer than 50 employees), but an equality plan cannot exist without a pay equity audit.