The data related to wheelchair need and supply displayed is based on a review of existing databases, annual reports, published data, organizations for aiding those with disabilities, and websites for wheelchair associations, service professionals, users, caregivers, and charitable foundations. The data displayed may be incomplete or partially inaccurate due to the following reasons:

1. The number of wheelchairs needed is estimated from the assumption that 1% of the population is in need of wheelchairs.
2. Some organizations distribute wheelchairs to different age groups (adult vs. child), in different geographies (urban vs. rural), or to different genders (male vs. female), thereby hindering effective comparison between groups.
3. Wheelchair distribution may be under reported due to undocumented distribution or over reported due to double counting of programs between partners. An independent agency that verified country-level distribution couldn't be found
4. The data assumes that all wheelchairs distributed had one recipient and are still in use from the time they were distributed.
5. A comprehensive list of non-government organizations and disabled people's organizations could not be provided due to time restrictions and because some DPOs did not have websites.
6. There are very few studies tailored to assessing the health care needs and resources for low-resource settings, which are often from those of high-resource settings. Methods for qualitatively measuring satisfaction, quality of life and impact are not tailored to demonstrate an understanding of cultural and ethical issues in working with disadvantaged populations.

source: Jhpiego Corporation. (2013). PHASE ONE DESK REVIEW: Research Study of Wheelchair and Wheelchair Services Provision in Low-Resource Settings.