搬離貧民區(qū)就能脫貧嗎,？

來源：紐約時(shí)報(bào) 

20年前，標(biāo)志性書籍《真正的窮人》(The Truly Disadvantaged)中強(qiáng)有力的論述,，以及關(guān)于社群隔離的負(fù)面效應(yīng)的權(quán)威研究,，使得聯(lián)邦貧困問題專家深受啟發(fā)，于是他們啟動(dòng)了一項(xiàng)政府實(shí)驗(yàn)項(xiàng)目,，讓855戶低收入家庭從貧困城區(qū)的公租屋中搬到經(jīng)濟(jì)狀況更好的社區(qū),。這些家庭絕大多數(shù)為非洲裔和西語(yǔ)裔。
項(xiàng)目的結(jié)果引發(fā)了激烈爭(zhēng)論,。
該計(jì)劃名為“搬向機(jī)遇”（Moving to Opportunity,，簡(jiǎn)稱MTO），始于比爾·克林頓(Bill Clinton)的第一個(gè)總統(tǒng)任期,。當(dāng)時(shí),，聯(lián)邦住房與城市發(fā)展部從巴爾的摩、波士頓,、芝加哥、洛杉磯和紐約隨機(jī)選擇了一大批有小孩的低收入家庭,。其中98%的家庭由女性支撐,；63%為黑人、32%為西語(yǔ)裔,、3%為白人,；26%有工作、76%領(lǐng)救濟(jì),，以2009年價(jià)格折算的家庭平均收入為1萬(wàn)2709美元（當(dāng)時(shí)約合8.7萬(wàn)元人民幣）,。
參與項(xiàng)目的共有4604戶家庭，分為三組,。一個(gè)實(shí)驗(yàn)組有1819戶,，政府向他們提供了“《住房法案》第8節(jié)規(guī)定的租賃補(bǔ)助券或代金券，但只能在1990年貧困率低于10%的人口普查區(qū)內(nèi)使用”,；855戶接受了提議,，參與到這項(xiàng)研究中,。第二組有1346戶，政府向他們提供的是更為傳統(tǒng)的租賃劵,，可以用在任何社區(qū),；848戶對(duì)此予以接受。
此外還有1439戶家庭留在公租屋社區(qū)里,，成為研究中的對(duì)照組,。聯(lián)邦住房與城市發(fā)展部表示，這一搬遷項(xiàng)目的目的在于,，測(cè)試“受助家庭進(jìn)入低貧困社區(qū)后在住房,、就業(yè)和教育成就方面的長(zhǎng)期效應(yīng)。”研究人員還研究了搬遷對(duì)領(lǐng)取租賃劵人員的健康影響,。
《美國(guó)經(jīng)濟(jì)評(píng)論》(American Economic Review)2013年5月刊發(fā)表了一篇題為《低收入家庭的長(zhǎng)期社區(qū)效應(yīng)：以“搬向機(jī)遇”項(xiàng)目為例》(Long-Term Neighborhood Effects on Low-Income Families: Evidence From Moving to Opportunity)的論文,。文中發(fā)現(xiàn)，相關(guān)家庭通過MTO項(xiàng)目遷出高貧困公租屋社區(qū)的10到15年后,，結(jié)果好壞參半,。
論文的第一作者芝加哥大學(xué)(University of Chicago)經(jīng)濟(jì)學(xué)教授延斯·路德維格(Jens Ludwig)是負(fù)責(zé)MTO最終評(píng)審的項(xiàng)目主管。他表示,，的確存在一些積極進(jìn)展,。他和六名論文合著者發(fā)現(xiàn)，受試者在“幾項(xiàng)關(guān)鍵的成人心理與生理健康指標(biāo)”上有所進(jìn)步,，比如糖尿病與肥胖癥的風(fēng)險(xiǎn)顯著降低,，以及“幸福感”有所提升。
不過,，路德維格的研究還發(fā)現(xiàn),，“光是變動(dòng)居住社區(qū)，或許并不足以改善底層家庭的就業(yè)或?qū)W業(yè)成就,。”他在文中指出,，這種允許家庭搬遷到“低貧困”地區(qū)的特殊租賃券“在一些方面沒有可觀察到的持續(xù)效應(yīng)，不管是經(jīng)濟(jì)上的自給自足,，還是孩子的教育成就,，就連實(shí)驗(yàn)伊始年齡尚小、沒有入學(xué)的孩子也如此,。”
在民主黨“三維智庫(kù)”(Third Way)本周發(fā)表的一篇后續(xù)文章中,，路德維格提出了類似結(jié)論。
美國(guó)的一些最為權(quán)威的貧困問題研究者,，比如哈佛社會(huì)學(xué)教授,、《真正的窮人》的作者威廉·朱利葉斯·威爾遜(William Julius Wilson)認(rèn)為，MTO項(xiàng)目存在設(shè)計(jì)缺陷,，從而引來了就業(yè)與學(xué)業(yè)方面未能有所改善的不妥結(jié)論,。
在寫給《紐約時(shí)報(bào)》的電子郵件中,，威爾遜指出，MTO項(xiàng)目里離開公租屋的家庭還是搬到了隔離社區(qū),，遠(yuǎn)離就業(yè)機(jī)會(huì),，而學(xué)校的糟糕程度也不相上下，子女往往還是去同樣的地方上學(xué),。他們的社會(huì)狀況只比之前好上一星半點(diǎn),。
此外，威爾遜寫道,，參與項(xiàng)目的成年人“此前一生均過著極為底層的生活,，無論到新社區(qū)里住了多久，早年所受的影響也不能完全消除,。”
在《美國(guó)社會(huì)學(xué)期刊》(American Journal of Sociology)2008年發(fā)表的一篇論文中,，哈佛社會(huì)學(xué)教授羅伯特·桑普森(Robert Sampson)提出，MTO項(xiàng)目還不如叫做“搬向不平等”,。
桑普森在寫給時(shí)報(bào)的電子郵件中指出,，參與MTO項(xiàng)目的許多成年人本已在極端貧困中浸淫了幾十年，而他們的子女在項(xiàng)目開始的時(shí)候平均年齡為11歲,，也已經(jīng)歷了早年的逆境,。“結(jié)果，”他寫道,。“在這樣的實(shí)驗(yàn)設(shè)計(jì)之下,，很難、甚至是不可能研究發(fā)展效應(yīng),，”因?yàn)檫@種設(shè)計(jì)沒有揭示出“嚴(yán)重貧困的滯后效應(yīng)”,。
雖然參與MTO項(xiàng)目的家庭搬到貧困與犯罪狀況稍好的社區(qū)，其新家所處的地段絕不是什么欣欣向榮之所,。桑普森繪制了一幅芝加哥地圖,，其中顯示，根據(jù)貧困率,、失業(yè)狀況,、領(lǐng)取救濟(jì)狀況,、女性支撐家庭的數(shù)量,、種族構(gòu)成和兒童人口密度進(jìn)行衡量的綜合指標(biāo)，絕大多數(shù)MTO家庭遷去的地方仍是“底層人口高度集中”的社區(qū),。
在另一項(xiàng)研究中,，來自蘭德公司(RAND Corporation)的研究員希瑟·施瓦茨(Heather Schwartz)得出的結(jié)論也與桑普森和威爾遜更為一致。在馬里蘭州蒙哥馬利縣,，施瓦茨研究了大多為少數(shù)族裔的低收入家庭學(xué)生的表現(xiàn),。該縣屬于華盛頓的郊區(qū),，經(jīng)濟(jì)富裕，以白人居民為主,。
蒙哥馬利縣采用了讓公租屋散布在各處的政策,。租戶中，72%為黑人,，16%為西語(yǔ)裔,。按照這一政策，這些租戶住在以白人為主的中產(chǎn)階級(jí)公寓樓里,。
這樣,，施瓦茨就能夠?qū)⒕幼≡诠馕堇锏暮⒆拥膶W(xué)業(yè)表現(xiàn)與大量來自富裕白人家庭的同學(xué)進(jìn)行比較；對(duì)照組的孩子上的學(xué)校則大部分容納的是少數(shù)族裔學(xué)生,，而且家庭貧困率要高得多,。
結(jié)果相當(dāng)驚人。住在公租屋的低收入少數(shù)族裔家庭的孩子,，一開始的時(shí)候數(shù)學(xué)分?jǐn)?shù)相當(dāng),。但是七年之后，同學(xué)中貧困率少于20%的孩子,，比起同學(xué)中貧困率在20%到80%之間的孩子,，成績(jī)遙遙領(lǐng)先。圖1的曲線顯示了其中的差異,。綠線代表那些上了較為富裕學(xué)校的貧困家庭孩子（定義為領(lǐng)取“免費(fèi)和優(yōu)惠餐”[FARM]的學(xué)生）的數(shù)學(xué)分?jǐn)?shù),，紅線則代表所上學(xué)校里領(lǐng)FARM比例要高得多的貧困家庭孩子的數(shù)學(xué)成績(jī)。
也許,，貧困代際傳遞最為重要的因素是,，嬰幼兒時(shí)期極端貧困帶來的長(zhǎng)期效應(yīng)。
美國(guó)兒科學(xué)會(huì)(American Academy of Pediatrics)2011年發(fā)表了一篇研究論文,，題為《嬰幼兒時(shí)期逆境與有害壓力的終生影響》(The Lifelong Effects of Early Childhood Adversity and Toxic Stress),。文中顯示，“早期經(jīng)歷和環(huán)境影響可在遺傳傾向方面留下持久痕跡,，從而影響正在成型的大腦構(gòu)造和長(zhǎng)期健康,。”這項(xiàng)兒科研究認(rèn)為，“早期逆境與后來在學(xué)習(xí),、行為及身心健康上的缺陷有關(guān),。”
嬰幼兒時(shí)期的壓力會(huì)影響“大腦結(jié)構(gòu)的發(fā)育”，從而“導(dǎo)致后來在學(xué)習(xí),、行為和健康方面基礎(chǔ)薄弱,。”
從這個(gè)角度看來，MTO項(xiàng)目的研究結(jié)果似乎并不意外。評(píng)估顯示,，比起留在公租屋社區(qū)的家庭,，拿到租賃券去低貧困社區(qū)居住的MTO參與者，在就業(yè)率與收入平等方面沒有進(jìn)展,，他們的子女的學(xué)業(yè)表現(xiàn)也并無進(jìn)步,。
首先，參與者似乎只獲得了不多的住房咨詢,，此外幾乎沒有獲得其他支持,。但更加深層的問題在于：多代貧窮可不僅僅是一個(gè)住房問題，這一點(diǎn)不言而喻,。即便是最具善意的單一措施,，也不可能解決得了它。
綜合多種措施可能會(huì)更加有效,。為弱勢(shì)群體境況代代相傳的現(xiàn)象,，尋找更加深層的原因，這是一個(gè)持續(xù)進(jìn)行的研究議程,。最近的一些論文,，比如《弱勢(shì)處境的傳承：居住多代的社區(qū)對(duì)認(rèn)知能力的影響》 (The Legacy of Disadvantage: Multigenerational Neighborhood Effects on Cognitive Ability)和《從時(shí)間角度看居民區(qū)效應(yīng)：長(zhǎng)期處于弱勢(shì)境地對(duì)高中畢業(yè)狀況的影響》 (Neighborhood Effects in Temporal Perspective: The Impact of Long-Term Exposure to Concentrated Disadvantage on High School Graduation)，都屬于這個(gè)進(jìn)程的一部分,。
MTO這項(xiàng)研究（目前已經(jīng)完成）遭受的批評(píng),，指出了可供探索的一些新途徑。盡管對(duì)于租賃券計(jì)劃結(jié)果的解釋,，變得富有爭(zhēng)議,，而且有點(diǎn)政治化，這個(gè)辯論本身卻可能具有建設(shè)性,。
巨大改變是有可能的實(shí)現(xiàn)的,，但下一步需要投入更多的資源，進(jìn)行更先進(jìn)的研究設(shè)計(jì),。
未來可能要做的事情,，包括對(duì)“知識(shí)就是力量”計(jì)劃(KIPP)等完全沉浸式學(xué)校系統(tǒng)進(jìn)行以證據(jù)為基礎(chǔ)的評(píng)估，以及更好地了解貧窮對(duì)大腦發(fā)育的影響,。也許最重要的是,，在“社區(qū)或?qū)W校”的討論中，把側(cè)重點(diǎn)放在縮小不同族裔的考分差異上,，哈佛大學(xué)經(jīng)濟(jì)學(xué)家小羅蘭·弗賴爾(Roland Fryer Jr.)和芝加哥大學(xué)經(jīng)濟(jì)學(xué)家史蒂芬·萊維特(Steven Levitt)說,。兩人認(rèn)為，在初中結(jié)束前消除考分差距,，“可能會(huì)是減少種族工資不平等過程的一個(gè)重要組成部分,。”
兩位作者寫道，“和早期的研究形成鮮明對(duì)比的是,，我們的研究證明,，當(dāng)我們對(duì)少數(shù)協(xié)變量進(jìn)行了控制后，黑人和白人進(jìn)入幼兒園前的考分差距就消失了,，”他們還表示,，“這是一個(gè)暗示性的證據(jù)，顯示學(xué)校教學(xué)質(zhì)量的差異,，可能是導(dǎo)致考分差距形成的重要原因之一,。我們也測(cè)試了用來解釋為什么黑人的成績(jī)每況愈下的其他假設(shè)，但它們沒有獲得任何實(shí)證的支持,。”
對(duì)于弱勢(shì)境地代代相傳的情況,，我們才剛剛開始有所了解；必須找出一個(gè)更好的辦法,，來對(duì)此加以干預(yù),，無論這個(gè)辦法是基于教育的，還是基于居民區(qū)的,，還是雙管齊下,。否則，我們?cè)鯓硬拍茏柚顾^續(xù)傳遞下去呢,？（更多資訊請(qǐng)瀏覽中國(guó)進(jìn)出口網(wǎng)）

Twenty years ago, federal poverty experts, inspired by the forceful arguments in the landmark book “The Truly Disadvantaged,” as well as by definitive research on the harmful effects of segregation, initiated a government experiment that moved 855 low-income predominantly African-American and Hispanic families out of public housing in poverty-stricken urban areas into less impoverished neighborhoods.
The results of the project have provoked an intense debate.
Under the aegis of the “Moving to Opportunity” program, begun during the first administration of Bill Clinton, the Department of Housing and Urban Development randomly seleced a large pool of low-income families with children living in public housing in Baltimore, Boston, Chicago, Los Angeles and New York. Ninety-eight percent of the families were headed by women; 63 percent were black, 32 percent Hispanic, and 3 percent white; 26 percent were employed, 76 percent were receiving welfare, and families had an average income of $12,709 in 2009 dollars.
These families, 4604 of them, to be exact, were then divided into three groups. An experimental group of 1,819 families was offered “Section 8 rental assistance certificates or vouchers that they could use only in census tracts with 1990 poverty rates below 10 percent”; 855 accepted the offer and became part of the study. A second group of 1,346 families was offered more traditional “Section 8” rent subsidy vouchers that could be used in any neighborhood; 848 accepted.
A control group composed of 1,439 families stayed in public housing and became part of the study. The purpose of the relocation initiative, according to Department of Housing and Urban Development, was to test the “long-term effects of access to low-poverty neighborhoods on the housing, employment and educational achievements of the assisted households.” Researchers also studied how relocation affected the health of those who accepted vouchers.
A paper published in the May 2013 issue of the American Economic Review, “Long-Term Neighborhood Effects on Low-Income Families: Evidence from Moving to Opportunity,” found that after 10 to 15 years, moving out of high-poverty public housing through the M.T.O. program showed mixed results.
There were some positive developments, according to the primary author of the paper, Jens Ludwig, a professor of economics at the University of Chicago and the project director for a final assessment of the M.T.O. program. Ludwig and his six co-authors found improvement in “several key adult mental and physical health outcomes.” These included significantly lowered risk of diabetes and obesity, as well as an improved level of “subjective well-being.”
But the Ludwig study also found that “changing neighborhoods alone may not be sufficient to improve labor market or schooling outcomes for very disadvantaged families.” Ludwig reported that this particular form of assistance from HUD –a housing voucher that allowed recipients to move into a “low poverty” area – had “no consistent detectable impacts on adult economic self-sufficiency or children’s educational achievement outcomes, even for children who were too young to have enrolled in school at baseline.”
Ludwig reported similar findings in a follow-up essay published this week by Third Way, a Democratic think tank.
Some of the nation’s most prominent poverty researchers, including William Julius Wilson, a professor of sociology at Harvard and the author of “The Truly Disadvantaged,” consider that the design of the M.T.O. project was flawed, leading to unwarranted conclusions about the lack of improvement in employment and schooling.
Wilson pointed out in an email to The Times that the families in the study who left public housing moved into segregated neighborhoods nonetheless, far from employment opportunities and with equally bad schools – often the same schools. Social conditions were only marginally better than those they had left.
In addition, Wilson wrote, the adults in the program “had been exposed all their lives to the effects of severely concentrated disadvantage, and no matter how long they are followed in their new neighborhoods, the effects of those earlier years are not fully erased.”
Robert Sampson, a professor of sociology at Harvard, argued in a 2008 essay published in the American Journal of Sociology that the project should have been called “Moving to Inequality.”
Sampson pointed out in an email that many of the adults in the program had lived in extreme poverty for decades and that the children, who were on average 11 years old when they entered the program, had spent their early years living in adversity. “The result,” he wrote, “is that developmental effects are difficult if not impossible to study in the research design,” which does not reveal the “lagged effects of severe disadvantage.”
While the M.T.O. participants moved to neighborhoods with somewhat less poverty and crime, their new homes were by no means in flourishing sections of the city. Sampson produced a map of Chicago showing that the overwhelming majority of families moved to areas that still qualified as communities of “high concentrated disadvantage” based on a measure combining poverty rates, unemployment, welfare receipt, female-headed households, racial composition and density of children.
In a separate study, Heather Schwartz, a researcher at the RAND Corporation, reached conclusions more in line with Sampson’s and Wilson’s. Schwartz examined the performance of low-income, mostly minority students in Montgomery County, Md., an affluent majority-white suburb of Washington.
The county adopted policies dispersing public housing so that many of the tenants, who were 72 percent black and 16 percent Hispanic, were housed in middle-class, largely white apartment complexes.
This allowed Schwartz to measure the performance of children from public housing who attended schools with large numbers of well-off white students, against the performance of those who attended schools with largely minority populations and much higher poverty rates.
The results are striking. The low-income minority children from public housing all started with similar math scores. But after seven years, those who went to schools wher fewer than 20 percent of their classmates were poor shot ahead of those who went to schools wher 20 to 80 percent of their classmates were poor. This difference in trajectories is shown in Figure 1, in which the green line tracks math scores for poor children (defined as those receiving “free and reduced-priced meals” – a.k.a. FARM recipients) in relatively affluent schools, and the red line tracks math scores for poor children attending schools with much higher percentages of fellow students receiving FARM assistance.
Perhaps the most important factors in the intergenerational transmission of disadvantage are the long-term effects on infants of living in extreme poverty.
A study published by the American Academy of Pediatrics in 2011, “The Lifelong Effects of Early Childhood Adversity and Toxic Stress,” shows that “early experiences and environmental influences can leave a lasting signature on the genetic predispositions that affect emerging brain architecture and long-term health.” The pediatric study links “early adversity to later impairments in learning, behavior, and both physical and mental well-being.”
Early childhood stress affects the “developing architecture of the brain” in ways “that create a weak foundation for later learning, behavior and health.”
Looked at this way, the M.T.O. findings — that participants who were given vouchers for housing in low-poverty neighborhoods made no gains in employment and wage equality compared with those left behind in public housing and that their children showed no improvement in school performance — do not seem surprising.
For one thing, participants appear to have been given little or no support other than modest housing counseling. But the issue is deeper than that: Multigenerational poverty is self-evidently more than a question of housing. It is unlikely to yield to even the best-intentioned one-dimensional approach.
Multifactorial approaches may be more productive. Recent papers such as “The Legacy of Disadvantage: Multigenerational Neighborhood Effects on Cognitive Ability” and “Neighborhood Effects in Temporal Perspective: The Impact of Long-Term Exposure to Concentrated Disadvantage on High School Graduation” are part of a continuing research agenda looking more profoundly into the causes of the intergenerational transmission of disadvantage.
The criticism of the M.T.O. study (which is now complete) points to new avenues for exploration. Even though the interpretation of the results of the housing voucher program has become contentious and somewhat politicized, the debate itself has the potential to be constructive.
Significant change is possible, but more resources and more sophisticated research design will be a necessary next step.
Lines of possible future inquiry include evidence-based evaluations of total-immersion school systems like the KIPP program and a better understanding of the effects of poverty on brain development. Perhaps most importantly, in the debate over “neighborhoods or schools,” would be a concentrated focus on reducing racial and ethnic discrepancies in test scores, according to the economists Roland Fryer Jr. of Harvard and Steven Levitt of the University of Chicago. Fryer and Levitt argue that the elimination of “the test score gap that arises by the end of junior high school may be a critical component of reducing racial wage inequality.”
The two authors write, “we demonstrate that in stark contrast to earlier studies, the black-white test score gap among incoming kindergartners disappears when we control for a small number of covariates.” They add, “There is suggestive evidence that differences in school quality may be an important part of the explanation. None of the other hypotheses we test to explain why blacks are losing ground receive any empirical backing.”
We have to figure out a better way to approach intervention, whether it’s education-based or neighborhood-based or both. Otherwise how can we interrupt the intergenerational transmission of disadvantage we are only beginning to understand?
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