As explained in detail here, Homewyse cost estimates are base on the Unit Cost Method.
This approach yields accurate results when the scope of work (description of exactly what work is to be performed), material quality and wage levels are known - and match the descriptions in the Homewyse calculators. In practice, the biggest variance between estimated and actual costs for homewyse calculators arises from wage differences. For this reason, the Installation Cost Calculators show a Low to High range for Labor costs. This Low to High range brackets mid-range Labor wages with good accuracy for the tasks at homewyse.
It is often the case that general contractors and designers are more likely to secure services at these prices - because they are familiar with fair pricing trends AND they are not afraid to negotiate for a fair price. Consumers who do not negotiate are likely to be quoted higher prices and will often pay higher than market prices. Caveat emptor!
Innacuracies due to imbalanced supply and demand of skilled labor do exist. Highly skilled specialty labor (e.g. certified installer for a premium countertop brand with controlled distribution) in a smaller community may not have any local competition. These vendors are under no obligation to set their prices at average levels and may price their services higher than national averages.
And... Homewyse does make mistakes in collecting, entering and publishing data and updates to the data. If you suspect an error, contact us (using the contact buttons on the calculator page in question, so that all data from that page will be sent to us with your note) with details of the error and correct pricing data. We'll review and correct mistakes quickly.
In situations where published homewyse pricing is not satisfactory, homewyse costs are fully editable/customizable by any user - for calculators that can be published and shared freely by the user. Learn more at https://youtu.be/f722LOcEJhg - and get started by browsing to app.homewyse.com .