Gender Impact Assessment is an ex-ante evaluation, analysis or assessment of a law, policy or programme that makes it possible to estimate in a preventative way the likelihood of a given decision to have positive, negative or neutral consequences for the state of equality between women and men. The central question of the GIA is: Does a law, policy or programme reduce, maintain or increase the gender inequalities between women and men?
The European Commission defines gender impact assessment as follows:
“Gender impact assessment is the process of comparing and assessing, according to gender relevant criteria, the current situation and trend with the expected development resulting from the introduction of the proposed policy.” 
The assessment involves a dual-pronged approach: the current gender-related position in relation to the policy under consideration, and the projected impacts on women and men once the policy has been implemented. It is important that the assessment is structured; that is to say systematic, analytical and documented.
The final aim of the GIA is to improve the design and the planning of the policy under consideration, in order to prevent a negative impact on gender equality and to strengthen gender equality through better designed, transformative legislation and policies. A primary objective is to adapt the policy to make sure that any discriminatory effects are either removed or mitigated. Beyond avoiding negative effects, a GIA can also be used in a more transformative way as a tool for defining gender equality objectives and formulating the policy so as to proactively promote gender equality.
The main steps to conduct a gender impact assessment are:
- Step 1: Definition of policy purpose, to produce a precise definition of the purpose of the planned policy or legislative intervention;
- Step 2: Checking gender relevance, to determine its gender relevance. This involves analysing whether it is or not susceptible to impact on gender equality.
- Step 3: Gender-sensitive analysis, which has a double focus. On the one hand, it should aim at understanding the present situation for the groups concerned by the public intervention and how this situation would evolve without public intervention. On the other hand, the analysis should include, to the extent possible in measurable terms, a prospective dimension: how is the planned intervention expected to change the existing situation.
- Step 4: Weighting the gender impact, establishing how the policy or legislative measure will contribute to gender equality, as well as assessing the foreseen impact in gender relations.
- Step 3: Findings and recommendations for the policy/legislative options. In this last step, the results of the analysis are presented and the impacts (positive or negative) of the policy/legislative initiative are highlighted. Recommendations on how to eliminate negative impacts and on how to enhance the positive ones are presented.
Other examples of guidelines on gender impact assessment:
- National Commission for the Promotion of Equality (2012). Gender Mainstreaming in Practice – Step-by-Step Guide for Gender Impact Assessment.
- European Commission. (1998). A Guide to Gender Impact Assessment.
 European Commission, “Evaluating Socio Economic Development, Sourcebook 2: Methods & Techniques. Gender impact assessment”, 2009.