# peermean

**Repository Path**: arlionn/peermean

## Basic Information

- **Project Name**: peermean
- **Description**: Stata module to compute mean of Peer firms
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2024-05-03
- **Last Updated**: 2024-05-03

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# peermean

## 1. 介绍
Stata module to compute mean of Peer firms. 

## 2. 安装

```stata
ssc install gitee, replace

gitee install arlionn/peermean/src, replace 
```

版本信息如下：

```stata
. which peermean

D:/stata/plus\p\peermean.ado
*! version  1.1  16Nov2023
*! Version: 1.0  2jan2008
*! Author: Yujun Lian, arlionn@163.com
```

## 3. 计算思路
Suppose there are 4 firms in an industry with output y {1, 2, 3, 4}. They are peers of each other.  When we consider firm A, its peers include firm B, firm C and firm D. The mean of output of firm A's peers equals y_mean{-A} = (2+3+4)/3.

    In general, the peer mean can be calculated by the following formula:
```stata
    --------------------------------------------------------------------

                   1
      y[peerx] = -----(y1+y2+...+y[i-1]+       +y[i+1]+...+y[N])
                  N-1
    
                   1
               = -----(y1+y2+...+y[i-1] + y[i] +y[i+1]+...+y[N] - y[i])
                  N-1   
                          
                   N               1  
               = -----(y_mean) - ----- y[i]
                  N-1             N-1 
                          
               = w1*y_mean - w2*y_i      
                   
    --------------------------------------------------------------------

    where, w1 = N/(N-1) and w2 = 1/(N-1)
```

## 4. 范例

```stata
    *-Data setup
    sysuse "nlsw88.dta", clear
    keep if industry<=3
    keep wage hours industry
    bysort industry: gen Ni = _n
    keep if Ni<=industry
    replace wage = int(wage)
    list, sepby(industry) clean

    *-peer mean
    peermean wage, by(industry)

    *-Results
    list indust wage Ni wage_peer, sepby(industry) abb(15)

     +-----------------------------------------------+
     |              industry   wage   Ni   wage_peer |
     |-----------------------------------------------|
  1. | Ag/Forestry/Fisheries     11    1           0 |
     |-----------------------------------------------|
  2. |                Mining      5    1          40 |
  3. |                Mining     40    2           5 |
     |-----------------------------------------------|
  4. |          Construction     11    1         8.5 |
  5. |          Construction     11    2         8.5 |
  6. |          Construction      6    3          11 |
     +-----------------------------------------------+

```


## 5. 参考文献
- Adhikari, B. K., & Agrawal, A. (2018). Peer influence on payout policies. Journal of Corporate Finance, 48, 615–637. [Link](https://doi.org/10.1016/j.jcorpfin.2017.12.010), [PDF](http://sci-hub.ren/10.1016/j.jcorpfin.2017.12.010), [Google](<https://scholar.google.com/scholar?q=Peer influence on payout policies>).
- Bird, A., Edwards, A., & Ruchti, T. G. (2018). Taxes and Peer Effects. The Accounting Review, 93(5), 97–117. [Link](https://doi.org/10.2308/accr-52004), [PDF](http://sci-hub.ren/10.2308/accr-52004), [Google](<https://scholar.google.com/scholar?q=Taxes and Peer Effects>).
- Chen, Y.-W., Chan, K., & Chang, Y. (2019). Peer effects on corporate cash holdings. International Review of Economics & Finance, 61, 213–227. [Link](https://doi.org/10.1016/j.iref.2019.02.008), [PDF](http://sci-hub.ren/10.1016/j.iref.2019.02.008), [Google](<https://scholar.google.com/scholar?q=Peer effects on corporate cash holdings>).
- Peng, Z., Lian, Y., & Forson, J. A. (2020). Peer effects in R&D investment policy: Evidence from China. International Journal of Finance & Economics, 26(3), 4516–4533. Portico. [Link](https://doi.org/10.1002/ijfe.2028), [PDF](http://sci-hub.ren/10.1002/ijfe.2028), [Google](<https://scholar.google.com/scholar?q=Peer effects in R&D investment policy: Evidence from China. International Journal of Finance & Economics, 26(3), 4516–4533>).