Scoping identifies impacts and alternatives that should be assessed in the EIA, creating a framework for the assessment process. Public involvement helps to determine priorities for the assessment of impacts and maximises public understanding and co-operation. In turn, this may influence the project design so that it better responds to the needs of the public. Indeed, early participation may result in a different, more sustainable outcome (Sheate & Atkinson, 1995). While re-working project designs can be costly for the developer, the investment is worthwhile if the final project is more likely to be authorised.

Participation during the scoping phase can strengthen the terms of reference for the EIA process where the assessment is being contracted out to consultants (Partridge, 1994). It has also been suggested that socio-economic problems, which tend to be neglected in EIAs, are more likely to be identified where the public are involved (Australian EIA Network, 1994).