We find that her supply curve seems to have been backward bending over the relatively high amounts of income she earned for each new episode of her show.
To the extent that the Oprah Supply Curve is backward bending, and to the extent that lessons drawn about Oprah can be applied to other high-income earners who supply unique services, it appears that higher tax rates might expand the quantity of services they supply while also increasing tax revenues.
Assuming her supply curve would be upward sloping at incomes that were lower than any of those that were observed, the estimates also imply that the curve is backward bending over relatively high amounts of income.
Using variation in the number of new episodes of The Oprah Winfrey Show per season over its 25 seasons, we found that Oprah's supply curve for new episodes of her show appears to have been backward bending over the relatively high amounts of income she earned for each episode.
For a forward bending posture, there is a backward bending
posture which balances it out.
This suggests that wage increases will not be effective in increasing supply of current workers and provides some evidence that aged care occupations have backward bending labour supply curves.
Some of the studies reviewed by Shields have found evidence of a backward bending labour supply function for RNs, pointing to the possibility that for some workers wage increases might lead to reduced labour supply.
Even with the different measure of supply, there is still strong evidence of a backward bending supply curve for the aged care occupations.
Indicated for patients suffering from degenerative diseases such as spinal stenosis and herniated discs, the DIAM Spinal Stabilization System addresses a wide range of surgical applications while its unique design offers support in both forward and backward bending
of the spine.
However, at relatively high wage rates the phenomenon of a backward bending labor supply occurs, indicating the dominancy of the income effect (see Link and Settle,  who discuss a case of backward bending supply of married professional nurses).
Because of the backward bending supply curve we can find another interesting characteristic.
The backward bending of the labor supply curve may also exist for a specific value when marginal utility from leisure is increasing (and not necessarily constant) as we assume in equation (1) above.