个人所得税的公平性体现(2)

Application of the Pareto Distribution

A central theme in reforming China’s PIT will undoubtedly be simplificationwith respect to both its base and rate schedules. The base issue will not bepursued further in this article.11 With regard to the rate schedules, clearly themost important schedule on which to focus one’s attention is the one that isapplied to wages and salaries. To analyze the revenue and distributive conse-quences of restructuring this schedule, detailed data on the PIT revenue col-lected by rate band are needed. If the restructuring is free to determine newband widths that bear no relationship to existing ones, data on national wagedistribution would also be necessary. Neither type of data at a sufficiently

disaggregated level is currently available in China. The extent of available

44THE CHINESE ECONOMY

Table 2

Composition of PIT Revenue, 2002

Amount inPercent

RMB bn of total

Wages and salaries56.146.4Of which: taxable at ≥ 25 percent9.78.0Business income of ICPEs18.515.3Interest, dividends, and bonuses38.431.7Of which: deposit interest30.124.8Other income8.16.7Total121.1100.0

Memorandum item

Total PIT revenue

As percent of total tax revenue6.9

As percent of GDP1.2

Source: State Administration of Taxation.

disaggregation of PIT revenue data is shown in Table 2: only revenue col-lected from the 25 percent rate band and above can be separately identifiedfrom the total in 2002 (this is the only year for which such a breakdown isavailable).

Lacking the requisite distribution data, the underlying wage distributionin China could be constructed on the assumption that it follows the Paretodistribution, which has been shown to be a reasonable assumption in manyempirical studies on income distribution in a large number of developed anddeveloping countries.12 The constructed distribution could then be used tosimulate the collection of PIT revenue by rate band of the progressive PITschedule applied to wages and salaries. The parameters of the model areestimated in such a way that the constructed distribution produces an out-come that is consistent with both the aggregate PIT revenue collection andthe subtotal amount collected at 25 percent and above in 2002.

Conceptual Framework

With the Pareto distribution, the distribution of the population over the rangeof wage levels (w), denoted by f(w), that is equal or above

some positive

MARCH–APRIL 200645

threshold w0, expressed as a fraction of total population at each w, is assumedto take the following functional form:

f(w) = β w-α-1, w ≥ w0 > 0,(1)

where β º α wa

coefficient. Hence, this distribution has two parameters: 0 > 0 is a constant and α > 1 is commonly known as the Paretoα and w

equation (1), the cumulative distribution function, denoted by F(w0. Given), of thePareto distribution, which gives the proportion of the population with wagesno greater than w, takes on a particularly simple form. By integrating f(w)over the wage interval [w0, w], one obtains

F(w) = 1 – (w0/w)α.(2)

Hence, the proportion of the population with wages above w is simply 1 –F(w) = (wα0/w). It follows that, if the size of the population is given by N,the number of wage earners with wages above w, denoted by n(w), wouldthen be

n(w) = N (w0/w)α,(3)

which is the most commonly cited formula associated with the Paretodistribution.

The average wage income for the entire population under the Pareto dis-tribution turns out to be13

v = w0 α/(α – 1),(4)

which says that it is proportional to the threshold income w

relatively simple matter with this distribution to ascertain both the number of0. It is also a

wage earners and the total wage income over any wage interval [a, b], whereb > a ≥ w0. The number of wage earners with wage income in this interval,denoted by na,b, is simply the product of N and the definite integral of f(w) over the interval, that is,

na,b = N β (a-α – b-α)/α.(5)

In the similar vein, total wage income in this interval, denoted by wbe the product of N and the definite integral of [w a,b, would

f(w)] over the interval,

that is,

wa,b = N β (a1-α – b1-α)/(α – 1).(6)

Hence, the average wage income in this interval is

46THE CHINESE ECONOMY

va,b ≡ wa,b/na,b = [(a1-α – b1-α)/(a-α – b-α)] [α/(α – 1)].(7)

Model Implementation

The objective is to ascertain the PIT revenue from wage income in each ofthe nine rate bands, for which actual data are not available. Since the basicmonthly allowance of RMB800 is equivalent to having a zero-rate band forincome below the said allowance, one could regard the rate schedule as hav-ing ten rate bands, starting with the zero percent rate and ending with the topmarginal rate of 45 percent. This schedule is given in column 1 of Table 3,with column 2 indicating the width of each band expressed in terms of an-nual wage income.

There are initially three unknown parameters: α, N, and w

w0. However, thegiven monthly allowance permits one to set 0 = 9,600, leaving only twoparameters to be estimated. Figure 1 shows how total PIT revenue behaves in

response to different combinations of α and N. The solution values of thesetwo parameters are found through numerical simulations so that the simu-lated PIT revenue outcome corresponds to the actual PIT revenue collectionin 2002 (see Table 2), for both (1) the global amount of RMB56.1 billion and

(2) the subtotal amount of RMB9.7 billion, which represents the PIT revenuecollected from rate bands from 25 percent to 45 percent. In Figure 2, thecurve G is an iso-PIT revenue contour that traces out the various combina-tions of α and N that would achieve the actual global PIT revenue target,while the curve M is anothe …… 此处隐藏：5749字，全部文档内容请下载后查看。喜欢就下载吧 ……