Jens Ludwig
Datos Biográficos
| ID | 3772038 |
|---|---|
| NOMBRE | Jens Ludwig |
| NOMBRES | Jens |
| APELLIDO | Ludwig |
| FIRMA | LUDWIG J |
| AFILIACIONES | Georgetown University |
| ORCID | 0000-0002-2998-1696 |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 51 |
| TOTAL DE CITAS | 248 |
| TOTAL COMO AUTOR | 51 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1997 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2025 |
| ÍNDICE H | 9 |
Does Nothing Stop a Bullet Like a Job? The Effects of Income on Crime
Do jobs and income-transfer programs affect crime? The answer depends on why one is asking the question, which shapes what one means by “crime.” Many studies focus on understanding why overall crime rates vary across people, places, and time; because 80% of all crimes are property offenses, that is what this type of research typically explains. But if the goal is to understand what to do about the crime problem, the focus should instead be on ser…
Crafts are great, but not for me’
Developing a sufficiently skilled and large workforce in the skilled trades constitutes a crucial bottleneck for implementing low-carbon transitions globally. However, research on strategies to increase apprentice numbers in vocational education and training (VET) in these Climate Crafts remains limited. Here, we examine the appeal of Climate Crafts among German adolescents. Grounded in the Social Cognitive Career Theory, the ordinal logistic reg…
The Inversion Problem
More and more machine learning is applied to human behavior. Increasingly these algorithms suffer from a hidden—but serious—problem. It arises because they often predict one thing while hoping for another. Take a recommender system: It predicts clicks but hopes to identify preferences. Or take an algorithm that automates a radiologist: It predicts in-the-moment diagnoses while hoping to identify their reflective judgments. Psychology shows us the…
Evaluating Contradictory Experimental and Nonexperimental Estimates of Neighborhood Effects on Economic Outcomes for Adults
Although non-experimental studies find robust neighborhood effects on adults, such findings have been challenged by results from the Moving to Opportunity (MTO) residential mobility experiment. Using a within-study comparison design, this paper compares experimental and non-experimental estimates from MTO and a parallel analysis of the Panel Study of Income Dynamics (PSID). Striking similarities were found between non-experimental estimates based…
Fragile Algorithms and Fallible Decision-Makers
Algorithms (in some form) are already widely used in the criminal justice system. We draw lessons from this experience for what is to come for the rest of society as machine learning diffuses. We find economists and other social scientists have a key role to play in shaping the impact of algorithms, in part through improving the tools used to build them
The Effect of Mentoring on School Attendance and Academic Outcomes
In response to budget problems, many urban school systems reduced resources for getting students to come to school, such as truancy officers. Chicago, for instance, in 1991, went from 150 truancy officers down to a total of zero. Is that a good idea? In this study, we explore the effects of increased support by a pro‐social adult, or “social capital,” delivered through a structured student monitoring and mentoring program called Check & Connect (…
Understanding Gun Violence
Response to Counterpoint
Reforming Housing Assistance
This article reviews current federal housing assistance policies and briefly summarizes research evidence about the efficacy of the different programs. We identify three key challenges that these programs face in meeting their stated objectives and suggest strategies for addressing them. The first challenge is the large variation in market conditions across the country, which makes it difficult to design assistance programs that are universally a…
Human Decisions and Machine Predictions
Can machine learning improve human decision making? Bail decisions provide a good test case. Millions of times each year, judges make jail-or-release decisions that hinge on a prediction of what a defendant would do if released. The concreteness of the prediction task combined with the volume of data available makes this a promising machine-learning application. Yet comparing the algorithm to judges proves complicated. First, the available data a…
Discrimination in the Age of Algorithms
The law forbids discrimination. But the ambiguity of human decision-making often makes it hard for the legal system to know whether anyone has discriminated. To understand how algorithms affect discrimination, we must understand how they affect the detection of discrimination. With the appropriate requirements in place, algorithms create the potential for new forms of transparency and hence opportunities to detect discrimination that are otherwis…
Thinking, Fast and Slow? Some Field Experiments to Reduce Crime and Dropout in Chicago
We present the results of three large-scale randomized controlled trials (RCTs) carried out in Chicago, testing interventions to reduce crime and dropout by changing the decision making of economically disadvantaged youth. We study a program called Becoming a Man (BAM), developed by the nonprofit Youth Guidance, in two RCTs implemented in 2009–2010 and 2013–2015. In the two studies participation in the program reduced total arrests during the int…
Summaries of Doctoral Dissertations
I was honored that Lee Alston asked me to be the convener for the Nevins Prize Competition this year. There were close to a dozen submissions spanning a
Prediction Policy Problems
Most empirical policy work focuses on causal inference. We argue an important class of policy problems does not require causal inference but instead requires predictive inference. Solving these “prediction policy problems” requires more than simple regression techniques, since these are tuned to generating unbiased estimates of coefficients rather than minimizing prediction error. We argue that new developments in the field of “machine learning” …
Long-Term Neighborhood Effects on Low-Income Families
We examine long-term neighborhood effects on low-income families using data from the Moving to Opportunity (MTO) randomized housing-mobility experiment. This experiment offered to some public-housing families but not to others the chance to move to less-disadvantaged neighborhoods. We show that ten to 15 years after baseline, MTO: (i) improves adult physical and mental health; (ii) has no detectable effect on economic outcomes or youth schooling …
The Effects of Housing Assistance on Labor Supply
This study estimates the effects of means-tested housing programs on labor supply using data from a randomized housing voucher wait-list lottery in Chicago. Economic theory is ambiguous about the expected sign of any labor supply response. We find that among working-age, able-bodied adults, housing voucher use reduces labor force participation by around 4 percentage points (6 percent) and quarterly earnings by $329 (10 percent), and increases Tem…
Neighborhood Effects on the Long-Term Well-Being of Low-Income Adults
Location, Location, Location It seems obvious that a person's residential neighborhood will influence their sense of well-being, but it has been difficult to nail down cause and effect. Ludwig et al. (p. 1505 ; see the Perspective by Sampson ) describe the analysis, 10 to 15 years onward, of a large-scale social experiment carried out in five U.S. cities in the mid 1990s. Several thousand residents of poor neighborhoods were given housing voucher…
Intercompany Energy Integration
Reusing heat through process integration in heat exchanger networks has long been a key measure for increasing energy efficiency in energy‐intensive industries. Thermal pinch analysis is commonly used for a systematic matching of process streams and thus planning of optimal process integration in large chemical plants. The possible savings increase with the amount of heat and the number of integrated process streams. Therefore co‐ siting of sever…
Controlling Crime
Criminal justice expenditures have more than doubled since the 1980s, dramatically increasing costs to the public. With state and local revenue shortfalls resulting from the recent recession, the question of whether crime control can be accomplished either with fewer resources or by investing those resources in areas other than the criminal justice system is all the more relevant. Controlling Crime considers alternative ways to reduce crime that …
Neighborhoods, Obesity, and Diabetes — A Randomized Social Experiment
BACKGROUND: The question of whether neighborhood environment contributes directly to the development of obesity and diabetes remains unresolved. The study reported on here uses data from a social experiment to assess the association of randomly assigned variation in neighborhood conditions with obesity and diabetes. METHODS: From 1994 through 1998, the Department of Housing and Urban Development (HUD) randomly assigned 4498 women with children li…
Crime policy and informal social control
Mechanism Experiments and Policy Evaluations
Randomized controlled trials are increasingly used to evaluate policies. How can we make these experiments as useful as possible for policy purposes? We argue greater use should be made of experiments that identify the behavioral mechanisms that are central to clearly specified policy questions, what we call "mechanism experiments." These types of experiments can be of great policy value even if the intervention that is tested (or its setting) do…
The costs of crime
What Can We Learn about Neighborhood Effects from the Moving to Opportunity Experiment
Experimental estimates from Moving to Opportunity (MTO) show no significant impacts of moves to lower‐poverty neighborhoods on adult economic self‐sufficiency four to seven years after random assignment. The authors disagree with Clampet‐Lundquist and Massey's claim that MTO was a weak intervention and therefore uninformative about neighborhood effects. MTO produced large changes in neighborhood environments that improved adult mental health and …
Does Head Start Improve Children's Life Chances? Evidence from a Regression Discontinuity Design
What Can We Learn about Neighborhood Effects from the Moving to Opportunity Experiment
Experimental estimates from Moving to Opportunity (MTO) show no significant impacts of moves to lower‐poverty neighborhoods on adult economic self‐sufficiency four to seven years after random assignment. The authors disagree with Clampet‐Lundquist and Massey's claim that MTO was a weak intervention and therefore uninformative about neighborhood effects. MTO produced large changes in neighborhood environments that improved adult mental health and …
Mechanism Experiments and Policy Evaluations
Randomized controlled trials are increasingly used to evaluate policies. How can we make these experiments as useful as possible for policy purposes? We argue greater use should be made of experiments that identify the behavioral mechanisms that are central to clearly specified policy questions, what we call "mechanism experiments." These types of experiments can be of great policy value even if the intervention that is tested (or its setting) do…
Aiming for evidence-based gun policy
The Benefits and Costs of Residential Mobility Programmes for the Poor
By enabling low-income families to move from high- to low-poverty neighbourhoods, tenant-based rental subsidies for poor families have the potential to reduce the degree of economic segregation in the US. This paper provides a framework for identifying the benefits and costs of such housing mobility programmes, and reviews the available empirical evidence on the net effects of quasi- or formal randomised housing mobility experiments. The best ava…
Does Gun Prevalence Affect Teen Gun Carrying After All
Previous research suggests that American adolescents usually have ready access to guns, and that the extent of misuse of guns by adolescents is not much affected by local gun prevalence or regulation. This “futility” claim is based on one interpretation of survey data from several cities, but has not been tested directly. Here we do so using microdata from a nationally representative survey, the 1995 National Survey of Adolescent Males. Using the…
Underground Gun Markets
This paper provides an economic analysis of underground gun markets drawing on interviews with gang members, gun dealers, professional thieves, prostitutes, police, public school security guards and teens in the city of Chicago, complemented by results from government surveys of recent arrestees in 22 cities plus administrative data for suicides, homicides, robberies, arrests and confiscated crime guns. We find evidence of considerable frictions …
The gender gap in reporting household gun ownership
OBJECTIVES: This study examined errors in estimating household gun ownership that result from interviewing only 1 adult per household. METHODS: Data from 2 recent telephone surveys and a series of in-person surveys were used to compare reports of household gun ownership by husbands and wives. RESULTS: In the telephone surveys, the rate of household gun ownership reported by husbands exceeded wives' reports by an average of 12 percentage points; h…
Reefer Madness
The pattern of misdemeanor marijuana arrests in New York City since the introduction of "broken windows" policing in 1994 is remarkable. By the year 2000, arrests on misdemeanor charges of smoking marijuana in public view (MPV) had reached 51,267 for the city, up 2,670 percent from 1,851 arrests in 1994. In 2000, misdemeanor MPV arrests accounted for 15 percent of all felony and misdemeanor arrests in New York City and 92 percent of total marijua…
Better Gun Enforcement, Less Crime
Research Summary: Project Safe Neighborhoods (PSN), which for the past several years has been the major federal initiative to combat gun violence, includes several elements (such as gun locks and other efforts to reduce gun availability) that research suggests are likely to have at best modest effects on gun crime. In general, enforcement activities targeted at the “demand side” of the underground gun market currently enjoy stronger empirical sup…
The Costs of Gun Violence against Children
Gun violence imposes significant costs on children, families, and American society as a whole. But these costs can be difficult to quantify, as much of the burden of gun violence results from intangible concerns about injury and death. This article explores several methods for estimating the costs of gun violence. One method is to assess how much Americans would be willing to pay to reduce the risk of gun violence. The authors use this "willingne…
Understanding Gun Violence
Reforming Housing Assistance
This article reviews current federal housing assistance policies and briefly summarizes research evidence about the efficacy of the different programs. We identify three key challenges that these programs face in meeting their stated objectives and suggest strategies for addressing them. The first challenge is the large variation in market conditions across the country, which makes it difficult to design assistance programs that are universally a…
Interpreting the WIC debate
Flawed gun policy research could endanger public safety
A highly publicized recent study by Lott and Mustard concludes that laws easing restrictions on licenses for carrying concealed firearms in public substantially reduce violent crime. Several serious flaws in the study render the authors' conclusions insupportable. These flaws include misclassification of gun-carrying laws, endogeneity of predictor variables, omission of confounding variables, and failure to control for the cyclical nature of crim…
The Effect of Mentoring on School Attendance and Academic Outcomes
In response to budget problems, many urban school systems reduced resources for getting students to come to school, such as truancy officers. Chicago, for instance, in 1991, went from 150 truancy officers down to a total of zero. Is that a good idea? In this study, we explore the effects of increased support by a pro‐social adult, or “social capital,” delivered through a structured student monitoring and mentoring program called Check & Connect (…
Crime policy and informal social control
The costs of crime
Anti-depressants, suicide, and drug regulation
Policymakers are increasingly concerned that a relatively new class of anti-depressant drugs, selective serotonin re-uptake inhibitors (SSRI), may increase the risk of suicide for at least some patients, particularly children. Prior randomized trials are not informative on this question because of small sample sizes and other limitations. Using variation across countries over time in SSRI sales and suicide, we find that an increase of one pill pe…
School-to-Work Programs in the United States
This paper provides one of the first detailed analyses of the training and finances of school-to-work (STW) programs in the United States. The data are from case studies of seven STW programs sponsored by firms of diverse size, type, and location. In almost every case, the firm paid at least some of the costs of general training. Most firms recoup some of these costs through rents captured by hiring former apprentices, but only in two cases do be…
Does Nothing Stop a Bullet Like a Job? The Effects of Income on Crime
Do jobs and income-transfer programs affect crime? The answer depends on why one is asking the question, which shapes what one means by “crime.” Many studies focus on understanding why overall crime rates vary across people, places, and time; because 80% of all crimes are property offenses, that is what this type of research typically explains. But if the goal is to understand what to do about the crime problem, the focus should instead be on ser…
Response to Counterpoint
Evaluating Gun‐policy Evaluations
Gun Self-Defense and Deterrence
Recent research on the prevalence of defensive gun use has prompted growing concern that government efforts to regulate gun ownership and use may be counterproductive. Estimates of defensive gun use from the National Crime Victimization Survey (on the order of 100,000 per year) appear to be too low. However, estimates from one-time telephone surveys (from 1.5 to 2.5 million per year) appear to be too high; even a modest rate of false positives ma…
The gun debate's new mythical number
Weighing the “burden of ‘acting white’”
Weighing the ?burden of ?acting white
Recent reports by ethnographic researchers and media sources suggest that many African American students view academic success as a form of “acting white,” and that peer pressure reduces their level of effort and performance. This article analyzes the National Education Longitudinal Study of 1988 to answer three questions: (1) do blacks experience greater alienation toward school than non-Hispanic whites?; (2) do blacks incur social penalties fro…
Flawed gun policy research could endanger public safety
A highly publicized recent study by Lott and Mustard concludes that laws easing restrictions on licenses for carrying concealed firearms in public substantially reduce violent crime. Several serious flaws in the study render the authors' conclusions insupportable. These flaws include misclassification of gun-carrying laws, endogeneity of predictor variables, omission of confounding variables, and failure to control for the cyclical nature of crim…
The gender gap in reporting household gun ownership
OBJECTIVES: This study examined errors in estimating household gun ownership that result from interviewing only 1 adult per household. METHODS: Data from 2 recent telephone surveys and a series of in-person surveys were used to compare reports of household gun ownership by husbands and wives. RESULTS: In the telephone surveys, the rate of household gun ownership reported by husbands exceeded wives' reports by an average of 12 percentage points; h…
Webster and Colleagues Respond
On the Other Hand individual dummy variables for each county and controlling for individual time trends in each county in difference estimates were among the many ways that we controlled for initial legal differences across counties. Changes in other gun laws were also accounted for, such as the existence of waiting periods (which are synonymous with background checks), the length of waiting periods, and penalties for using guns during the commis…
More Guns, Less Crime
Ludwig et al. Respond
Ludwig et al. Respond Jens Ludwig, Philip J. Cook, and Tom W. Smith CopyRight https://doi.org/10.2105/AJPH.89.9.1442-a Published Online: October 07, 2011
Homicide and Suicide Rates Associated With Implementation of the Brady Handgun Violence Prevention Act
CONTEXT: In February 1994, the Brady Handgun Violence Prevention Act established a nationwide requirement that licensed firearms dealers observe a waiting period and initiate a background check for handgun sales. The effects of this act have not been analyzed. OBJECTIVE: To determine whether implementation of the Brady Act was associated with reductions in homicide and suicide rates. DESIGN AND SETTING: Analysis of vital statistics data in the Un…
Gun Self-Defense and Deterrence
Recent research on the prevalence of defensive gun use has prompted growing concern that government efforts to regulate gun ownership and use may be counterproductive. Estimates of defensive gun use from the National Crime Victimization Survey (on the order of 100,000 per year) appear to be too low. However, estimates from one-time telephone surveys (from 1.5 to 2.5 million per year) appear to be too high; even a modest rate of false positives ma…
School-to-Work Programs in the United States
This paper provides one of the first detailed analyses of the training and finances of school-to-work (STW) programs in the United States. The data are from case studies of seven STW programs sponsored by firms of diverse size, type, and location. In almost every case, the firm paid at least some of the costs of general training. Most firms recoup some of these costs through rents captured by hiring former apprentices, but only in two cases do be…
Urban Poverty and Juvenile Crime
This paper uses data from a randomized housing-mobility experiment to study the effects of relocating families from high- to low-poverty neighborhoods on juvenile crime. Outcome measures come from juvenile arrest records taken from government administrative data. Our findings seem to suggest that providing families with the opportunity to move to lower-poverty neighborhoods reduces violent criminal behavior by teens
The Costs of Gun Violence against Children
Gun violence imposes significant costs on children, families, and American society as a whole. But these costs can be difficult to quantify, as much of the burden of gun violence results from intangible concerns about injury and death. This article explores several methods for estimating the costs of gun violence. One method is to assess how much Americans would be willing to pay to reduce the risk of gun violence. The authors use this "willingne…
The Benefits and Costs of Residential Mobility Programmes for the Poor
By enabling low-income families to move from high- to low-poverty neighbourhoods, tenant-based rental subsidies for poor families have the potential to reduce the degree of economic segregation in the US. This paper provides a framework for identifying the benefits and costs of such housing mobility programmes, and reviews the available empirical evidence on the net effects of quasi- or formal randomised housing mobility experiments. The best ava…
Evaluating Gun‐policy Evaluations
The Endogeneity Problem in Developmental Studies
Estimates of developmental models of processes involving contextual influences (e.g., child care arrangements, divorce, parenting, neighborhood location, peers) are subject to bias if, as is often the case, the contexts are influenced by the actions of ei-ther the individuals being studied or their parents or teachers. We assessed the nature of the endogeneity biases that may result, discuss the importance of such biases in practice, and suggest …
Does Gun Prevalence Affect Teen Gun Carrying After All
Previous research suggests that American adolescents usually have ready access to guns, and that the extent of misuse of guns by adolescents is not much affected by local gun prevalence or regulation. This “futility” claim is based on one interpretation of survey data from several cities, but has not been tested directly. Here we do so using microdata from a nationally representative survey, the 1995 National Survey of Adolescent Males. Using the…
Neighborhood Effects on Crime for Female and Male Youth
The Moving to Opportunity (MTO) demonstration assigned housing vouchers via random lottery to public housing residents in five cities. We use the exogenous variation in residential locations generated by MTO to estimate neighborhood effects on youth crime and delinquency. The offer to relocate to lower-poverty areas reduces arrests among female youth for violent and property crimes, relative to a control group. For males the offer to relocate red…
Neighborhood Effects on Crime for Female and Male Youth
The Moving to Opportunity (MTO) demonstration assigned housing vouchers via random lottery to public housing residents in five cities. We use the exogenous variation in residential locations generated by MTO to estimate neighborhood effects on youth crime and delinquency. The offer to relocate to lower-poverty areas reduces arrests among female youth for violent and property crimes, relative to a control group. For males the offer to relocate red…
Better Gun Enforcement, Less Crime
Research Summary: Project Safe Neighborhoods (PSN), which for the past several years has been the major federal initiative to combat gun violence, includes several elements (such as gun locks and other efforts to reduce gun availability) that research suggests are likely to have at best modest effects on gun crime. In general, enforcement activities targeted at the “demand side” of the underground gun market currently enjoy stronger empirical sup…
Interpreting the WIC debate
Anti-depressants, suicide, and drug regulation
Policymakers are increasingly concerned that a relatively new class of anti-depressant drugs, selective serotonin re-uptake inhibitors (SSRI), may increase the risk of suicide for at least some patients, particularly children. Prior randomized trials are not informative on this question because of small sample sizes and other limitations. Using variation across countries over time in SSRI sales and suicide, we find that an increase of one pill pe…
The social costs of gun ownership
Aiming for evidence-based gun policy
Does Head Start Improve Children's Life Chances? Evidence from a Regression Discontinuity Design
Economics (30 obras) · Psychology (27 obras) · Medicine (25 obras) · Political science (22 obras) · Computer Science (20 obras) · Crime Patterns and Interventions (20 obras) · Sociology (17 obras) · Criminology (16 obras) · Gun Ownership and Violence Research (16 obras) · Demographic economics (15 obras)