﻿ 柠檬现象的普遍性研究 Researches on Universality of the Lemon Phenomenon

Advances in Applied Mathematics
Vol.04 No.02(2015), Article ID:15179,8 pages
10.12677/AAM.2015.42013

Researches on Universality of the Lemon Phenomenon

Jia Guo

School of Mathematics and Computational Science, Sun Yat-sen University, Guangzhou Guangdong

Email: gg1993118@sina.com

Received: Apr. 15th, 2015; accepted: May 1st, 2015; published: May 7th, 2015

Copyright © 2015 by author and Hans Publishers Inc.

ABSTRACT

As a common phenomenon in the market economy, the Market for Lemons, also called Akerlof Model, precisely describes the problems of quality and uncertainty. This conception was published by George Akerlof in 1970 and his work laid the foundation for Asymmetric Information. Based on the economic conception and interpretation, this paper discusses the Lemon Phenomenon through a mathematic model which is depended on simple stochastic simulation. With the well-established model and the results of data gained from simulation, it is easy to evaluate the concrete performance that the Market for Lemon shows in the second-hand car market. Finally, by extending to other kinds of areas and analyzing various sorts of Lemon Phenomenon, this paper summarizes different perspectives from previous works on Asymmetric Information and puts forward several ways to deal with the situation.

Keywords:Lemon Phenomenon, Asymmetric Information, Stochastic Simulation, Mathematic Model

Email: gg1993118@sina.com

1. 柠檬市场模型简介

1.1. 基本定义

1.2. 形成原因

2. 基于二手车市场的随机模拟数学模型

2.1. 基本假设

1) 买方对商品的信息了解程度远低于卖方；

2) 买方购买时足够理性；

3) 二手车市场中商品真实价值(质量)为均匀分布；

4) 市场中的车辆总数用N表示，当N很大时具有一般性；

5) 每当有商家退出市场时，总会有新商家补入，并同样为均匀分布的真实价值；

6) 大部分商家大致按真实价值出价。

2.2. 变量说明

N：市场中车辆总数；

M：顾客批数；

K：每批淘汰的商家数；

P：市场中每辆车的价格；

Q：市场中每辆车的真实价值系数，0到1均匀分布，0为最劣等商品，1为最优等商品；

：市场中所有车辆的平均价格；

：市场中所有车辆价格的标准差；

P2：某时刻顾客的最高心理出价；

：市场中商品的平均价值系数；

2.3. 建立模型

(1)

(2)

(3)

2.4. 模型求解及分析

Table 2. MATLAB simulated results of Lemon Phenomenon, with increasing M and psychological index equaled to 2/3

Table 3. MATLAB simulated results of Lemon Phenomenon, with increasing M and psychological index equaled to 3/4

(4)

(5)

(6)

(7)

2.5. 结论

3. 其他领域中的柠檬现象

3.1. 劣币驱逐良币

16世纪，英国经济学家格雷欣发现了一种市场中奇特的现象，如果有两种实际价值不同但名义上却价值相等的货币在市场中流通，那么实际价值较高的一种必然会退出市场，它们大部分会被收藏起来，或者输出国外，因此市场中流通的就只有实际价值较低的那种货币。这种现象就是劣币驱逐良币现象，人们称之为“格雷欣法则”。

3.2. 电子商务市场

3.3. 就业市场

3.4. 绿色食品贸易

4. 柠檬市场的对策

4.1. 信号传递广告效应

4.2. 政府干预

4.3. 第三方介入

4.4. 针对顾客需求着重技术创新

Researches on Universality of the Lemon Phenomenon. 应用数学进展,02,96-104. doi: 10.12677/AAM.2015.42013

1. 1. Akerlo, G.A. (1970) The market for lemons: Quality uncertainty and the market mechanism. Quarterly Journal of Eco-nomics, 84, 488-500.

2. 2. 萧清 (1984) 中国古代货币史. 人民出版社, 北京.

3. 3. 陈林冉 (2011) 劣币驱逐良币规律在中国历史上的表现. 现代商业, 15, 35.

4. 4. 李修平 (2010) 浅析劣币驱逐良币规律在中国货币史的表现. 中国商界(下半月), 6, 72.

5. 5. 王国才 (2014) 对市场经济中“劣币驱逐良币”的现象分析. 内江科技, 10, 119-120.

6. 6. 李松, 赵瑞涛 (2010) 电子商务“柠檬市场”现象的经济学分析. 社会科学战线, 11, 207-210.

7. 7. 徐杰华, 张坚 (2008) 就业中的“柠檬市场”现象与对策的试验验证. 现代经济(现代物业下半月刊), S1, 56-57.

8. 8. 王永奇 (2004) 柠檬市场与绿色食品贸易政策效应. 国际贸易问题, 4, 27-31.

9. 9. 周波 (2010) 柠檬市场治理机制研究述评. 经济学动态, 3, 131-135.

10. 10. Phillip, N. (1974) Advertising as information. Journal of Politics, 4, 796-821.

11. 11. Kihlstrom, R.E. and Riordan, M.H. (1984) Advertising as a signal. The Journal of Political Economy, 92, 427-450.

12. 12. 贺新峰, 杨昌明 (2005) 产业集群的“柠檬市场”现象分析及对策. 当代经济管理, 6, 100-102.

13. 13. Garella, P. (1989) Adverse selection and the middleman. Economica, 56, 395-399.

14. 14. Albano, G. and Lizzeri, A. (2001) Strategic certification and provision of quality. International Economic Journal, 42, 267-283.

clc;clear;

N=100000;

j=1;

k=1000;

QQ=zeros(k,2);

lum=unifrnd(0.5,1,1,k);

fori=1:k

Q=rand(1,N);

P=10^5*Q;

flag=find(P>mean(P)+std(P));

P(flag)=[];

Q(flag)=[];

Q=[Q,rand(1,length(flag))];

for M=1:10000

P=10^5*Q;

P=lum(i)*P+(1-lum(i))*mean(P);

m=mean(P);s=std(P);

flag=find(P>m+s);

P(flag)=[];

Q(flag)=[];

Q=[Q,unifrnd(0,1,1,length(flag))];

end

QQ(j,2)=mean(Q);

j=j+1;

end

QQ(:,1)=lum;

QQ