1. Customer satisfaction
This is an important criteria in which after sales experience of customers who have purchased an item specially for plantar fasciitis is strongly considered. On a scale of 1 to 5, this needs to be atleast 4+ for any serious rating on this website. This information is accessible at independent forums, verified customers at Amazon/EBay and other ecommerce sites. To illustrate this point, this is how customer satisfaction research is done (see image).
2. Orthotic standards recommended by APMA (American Podiatric Medical Association)
APMA provides a seal of approval for products that are good for foot health. The list on their website is not always updated but information about any popular product can always be obtained on special request. They are a helpful group with an objective to promote good health. The products on this website can receive good rating only if it's approved by APMA.
3. Available at renowned ecommerce sites and always in stock
It's important that buyer protection is available for plantar fasciitis products. Individual company online sales page generally do not provide buyer protection. This is however, available at reliable websites like Amazon or Ebay. There is no point in rating any product good if it's not practically easy to buy with buyer protection.
4. Brand value and past record
Past record of the company and similar line of products is an important consideration as it makes the ratings reliable.