Some projects may require comprehensive HIAs, but most projects will not. For those projects that do require new data collection, some level of specialty consulting support may be required. Local and national public health authorities should always be consulted, since their knowledge and expertise is critical and is grounded in the realities of the project's location and overall country situation. In addition, specialized support or an independent review process may help identify gaps or other issues not fully considered by an internal team, and may enhance validity and transparency.