The Labor Market Impact of Immigration 政府政策限制或鼓勵移民將影響勞動力之供給 美國主要政策改變,使得移民人數在1965年後增加 移民人數 從1965年250,000 到2000年超過1,000,000 移民對本地(native-born)勞工的影響

The Short-Run Impact of Immigration When Immigrants and Natives Are Perfect Substitutes In the Short-Run: with capital held fixed Immigration使勞動供給線右移: 薪水下降:從w0 to w1 總就業增加:從 N0 到 E1. 薪水下降願意工作之native worker減少: 從N0 到 N1 Immigrants “take job away” from natives by reducing the native wage and convincing some native workers that it is no longer worthwhile to work Dollars Supply w0 w1 Demand N0 Employment E1 N1

The Short-Run Impact of Immigration when Immigrants and Natives are Complements Immigration makes natives more productive: native worker: 生產力上升使薪水增加:從W0到W1 薪水增加讓原本覺得薪水低不願工作 的人出來工作:N0到N1 native worker勞動需求線外移 薪水和就業人數增加 w1 w0 Dollars Supply Demand N1 N0 Employment (native worker)

Short-Run versus Long-Run Effects Suppose immigrants and native are perfect substitutes In the Short-Run: immigrants lower the wage but raise the returns to capital 較低的薪資使廠商擴充資本以增加獲利 Demand curve of labor 右移 重要的是右移多少? 只右移一點,受競爭的勞工仍會收到比原本低的薪資 劇烈右移,the negative wage effects might disappear

The Long-Run Impact of Immigration When Immigrants and Natives Are Perfect Substitutes Immigration 使 the labor supply curve 外移 薪資下降:從 w0 到 w1. Over time, capital expands as firms take advantage of the cheaper workforce, shifting out the labor demand curve and restoring the original wage and level of native employment. Dollars Supply w0 w1 Demand N0 Employment N0 + Immigrants

Cobb-Douglas production function q=AKα L1-α r = $1*α AKα-1 L1-α w = $1*(1-α) AKα L-α r = αΑ(K/L)α-1 w = (1-α)Α(K/L)α

The Mariel Boatlift 1980年馬列爾偷渡事件，有125,000古巴人偷渡到邁阿密 The Cubans most were low-skill workers 大量移民導致邁阿密labor force grew by 7%

The Mariel Flow Unemployment rate of blacks in Miami 8.3 -> 9.6 +1.3 in comparison 10.3->12.6 +2.3 可能是那段時間經濟環境惡化 這樣看來the mariel flow 還減低了邁阿密地區的失業成長率for1%

The Mariel Flow that did not happen Unemployment rate of blacks in Miami 10.1 -> 13.7 +3.6 in comparison 11.5->8.8 -2.7

The short-run labor demand curve implied by different natural experiments (a)inceased immigration doesn’t affect the wage ,the SR demand curve is prrfectly elastic (a)inceased in the minimum wage doesn’t affect the employment ,the SR demand curve is prrfectly inelastic Dollars Employment E* (b) NJ-Pennsylvania minimum wage (a) Mariel w* D Demand curve implied by Mariel natural experiment Demand curve implied by minimum wage natural experiment

在假設中,移民潮會對本地黑人工人造成很大衝擊 但是事實證明其實沒有什麼太大影響 The minimum wage increase in New Jersey 原本假定就業率會比沒實施最低工資的地區相對下降 但是結果證明最低工資的實施對就業率沒影響

The mariel △w=α △E+other variables New Jersey minimum wage △E=β △w+other variables There is zero correlation between the dependent variables and independent variables ,so the coefficientα ,βis nearly=0

結 The immigration induced changes in supply have little impact on wage The increase in minimum wage has little impact on employment

The native labor market’s response to immigration Dollars PPT w0 Demand (b) Pittsburgh Employment S0 S3 w* PLA wLA (a) Los Angeles S1 S2

Trends in California’s population

Scatter Diagram Relating Wages and Immigration for Native Skill Groups

2 variables : Wage growth for a skill group of native working man over a particular decade (1960~2000) To 非本地勞工的變動量 負相關 資料顯示:skill worker immigration increase10% the wage falls 3~4%