nderstanding what voluntary sustainability standards deliver on the ground is an important part of the debate about their ongoing relevance to business, policy makers and the public.

The ISEAL Alliance commissioned 3Keel and the University of Oxford to address this question by reviewing the evidence on whether standards systems drive the adoption of sustainable practices.

We systematically filtered 116 studies from an original body of more than 13,000 studies, based on relevance, scope and methodological robustness. This body of evidence was reviewed for six thematic areas: conservation and biodiversity, use of inputs, community development, occupational health and safety, management systems, and good production practices. These themes represent a range of environmental, social and economic aspects of sustainability. We added additional insight from analysis of monitoring data from six standards systems, and from key informant interviews.

Most of the studies reviewed present evidence that certified entities are more likely to adopt improved practices than non-certified entities. The evidence is more consistent for health and safety and community development practices than for the others themes. This makes sense, because certification is a plausible driver of practices that are outside existing norms (such as greater engagement with local communities) and practices that are easy for auditors to detect (like use of Personal Protective Equipment), and which therefore have to be in place for an organisation to gain a certificate.

Important enablers of practice adoption were identified. Amongst these perhaps the most important is external technical, institutional or financial support: for smallholders in particular, certification results in the biggest changes to practice when support is also received.

We also found evidence that certification audits drives some practice adoption. Audits also seem to play a role in ensuring that sustainable practices are maintained.

However, standards do not always drive the adoption of sustainable practices. The common situations where evidence of practice adoption is more mixed are:

• Where existing levels of practice are high (or the requirements of the standard are low)
• When practice adoption occurs largely pre-certification (note this is anecdotal as there are almost no data is available on this ‘pre-certification’ phase).
• Where the gap between existing practice and the standard is too great.
• Practices that are harder for auditors and researchers to detect.

We develop a series of recommendations from these findings, covering the need for rigorous assessment of the impact of standards, the need to develop innovative capacity to capture ‘hard to detect’ practices, and increased investment in technical, financial and institutional support to producers as a ‘multiplier’ of investment in sustainability standards.