Fig 1.
Fairness benchmarks representing the statistical relationships between the quintile salary shares of professional athletes (, i = 1, 2, 3, 4, 5) and the Gini index for professional athletes’ salaries (GiniS), where 0 < GiniS < 1.
(A) Bottom 20%. (B) Second 20%. (C) Third 20%. (D) Fourth 20%. (E) Top 20%. Note that the scale of , and
is between 0.00 and 0.25. The scale of
is between 0.00 and 0.30 while the scale of
is between 0.00 and 1.00.
Table 1.
The descriptive statistics of data on quintile income shares and income Gini index of Thailand from 1988 to 2021.
Fig 2.
Scatter plots of the Cartesian coordinates of income Gini index and quintile income shares (, i = 1, 2, 3, 4, 5) of Thailand from 1988 to 2021.
(A) Bottom 20% (). (B) Second 20% (
). (C) Third 20% (
). (D) Fourth 20% (
). (E) Top 20% (
). Note that the scale of
, and
is between 0.00 and 0.25. The scale of
is between 0.00 and 0.30 while the scale of
is between 0.00 and 1.00.
Table 2.
Thailand’s actual quintile income shares, fair quintile income shares based on SH method, optimal (fair) quintile income shares representing feasible income equality based on PK method, and their corresponding values of income Gini index.
Fig 3.
The degree of unfairness in quintile income shares of Thailand from 1988 to 2021 as measured by the difference between actual quintile income shares and fair quintile income shares (Δ) according to SH method.
Note that the scale of Δ is between– 0.08 and 0.08.
Fig 4.
Actual quintile income shares of Thailand and their corresponding optimal (fair) quintile income shares from 1988 to 2021.
(A) Bottom 20%. (B) Second 20%. (C) Third 20%. (D) Fourth 20%. (E) Top 20%. Note that the scale of , and
is between 0.00 and 0.20. The scale of
is between 0.10 and 0.30 while the scale of
is between 0.25 and 0.70.
Fig 5.
The degree of unfairness in quintile income shares of Thailand from 1988 to 2021 as measured by the difference between actual quintile income shares and optimal (fair) quintile income shares (Δ) based on PK method.
Note that the scale of Δ is between– 0.15 and 0.35.
Table 3.
Actual quintile income shares of Thailand in 2015, fair quintile income shares being consistent with the targeted income Gini index of 0.410, and optimal (fair) quintile income shares representing feasible income equality with the income Gini index of 0.137.
Fig 6.
Lorenz plot of actual income distribution by quintile of Thailand in 2015 corresponding to the income Gini index of 0.445, Lorenz plot of fair income distribution by quintile based on SH method that is consistent with the targeted Gini index of 0.410, and Lorenz plot of optimal (fair) income distribution by quintile representing feasible income equality based on PK method with the Gini index of 0.137.