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The objective of this work was to systematically evaluate the effects of formulation composition on subcutaneous injection site pain (ISP) using matrices comprising of common pharmaceutical excipients. Two randomized, blinded, crossover studies in healthy subjects were conducted at a single site, where subjects received 1 mL SC injections of the buffer matrices. ISP intensity was measured using a 100 mm visual analogue scale (VAS), which was then analyzed via heatmap, categorical grouping, subgroup analysis, and paired delta analysis. Buffer type, buffer concentration and tonicity agent showed a substantial impact on ISP. Citrate buffer demonstrated a higher ISP than acetate buffer or saline). The 20 mM citrate buffer was more painful than 10 or 5 mM citrate buffers. NaCl and propylene glycol were significantly more painful than sugar alcohols (mannitol, sucrose, trehalose or glycerol). Histidine buffers exhibited ISP in the descending order of 150 mM > 75 mM > 25 mM > 0 mM NaCl, while histidine buffers containing Arginine-HCl at 0, 50, or 150 mM all showed very low ISP. Histidine buffer at pH 6.5 showed a lower ISP than pH 5.7. This systematic study via orthogonal analyses demonstrated that subcutaneous ISP is significantly influenced by solution composition.

Analyzing account-level data from an account aggregator, we find that households increase consumption when they receive expected tax refunds, as if they face liquidity constraints. However, these same households smooth consumption when making payments in other years, primarily by transferring funds among liquid accounts. Even households carrying credit card debt smooth consumption when making payments, and even highly liquid households spend out of refunds. This behavior is inconsistent with pure liquidity constraints or hand-to-mouth behavior and is most consistent with a mental accounting life-cycle model. (JEL D12, E21, G51, H24, H31)

This paper evaluates the Car Allowance Rebate System (CARS ) by comparing the vehicle purchases and disposals of households with eligible “clunkers” to those of households with similar but ineligible vehicles. CARS caused roughly 500,000 purchases during the program period. The provision of liquidity, through a rebate usable as a down payment, was critical in generating this large response. Participation was rare among households that owned clunkers with outstanding loans, which required loan repayment. This decline in participation is attributed to households’ preference for lower down payments and distinguished from the effects of income, other indebtedness, and the program subsidy. (JEL E23, E62, G51, H24, H31)

© 2019 The Ohio State University Using variation in minimum wages across cities and controlling for differences in business-cycle factors and long-run local economic trends, we find that following minimum wage increases, both, prices and nominal spending rise modestly. These gains are larger for certain subcategories of goods such as food away from home and in locations where low-wage workers account for a larger share of employment. Further, minimum wage increases are associated with reduced total debt among households with low credit scores, higher auto debt, and increased access to credit.

This essay argues for a re-reading of the lament in Psalm 22:1–5, 9–11 as Christian Scripture. This reading of the Old Testament as Christian Scripture redresses an imbalance in Christian theology, which tends to highlight difficulties in Jesus’ cry of dereliction but obscures its lament. This lament is central to the cross as solidarity with the experience of human suffering as betrayal by God and as an invitation for humanity to cry out for God’s response, found ultimately in the cross. In particular, the essay offers a new, feminist, birth-sensitive interpretation of Psalm 22:9–11 and a new, feminist translation of Psalm 22:10b, accenting God’s motherhood in the passage.

We evaluate the consistency of two methods for estimating the effect of an economic policy: (i) asking people how the policy caused them to change their behavior (reported effects) and (ii) inferring this change using data on behavior and differences in treatment across people (revealed-preference estimates). Both methods are widely used to measure spending caused by increases in liquidity. Using federal stimulus payments disbursed quasi-randomly in 2008, we find larger revealed-preference estimates of spending propensities for households who report greater spending responses, and the methods produce similar average propensities. But evidence is mixed on the relationship between spending propensities and liquidity. (JEL C83, D14, D91, E62, H24, H31)

The objective of this work was to systematically evaluate the effects of formulation composition on subcutaneous injection site pain (ISP) using matrices comprising of common pharmaceutical excipients.Two randomized, blinded, crossover studies in healthy subjects were conducted at a single site, where subjects received 1 mL SC injections of the buffer matrices. ISP intensity was measured using a 100 mm visual analogue scale (VAS), which was then analyzed via heatmap, categorical grouping, subgroup analysis, and paired delta analysis.Buffer type, buffer concentration and tonicity agent showed a substantial impact on ISP. Citrate buffer demonstrated a higher ISP than acetate buffer or saline). The 20 mM citrate buffer was more painful than 10 or 5 mM citrate buffers. NaCl and propylene glycol were significantly more painful than sugar alcohols (mannitol, sucrose, trehalose or glycerol). Histidine buffers exhibited ISP in the descending order of 150 mM 75 mM 25 mM 0 mM NaCl, while histidine buffers containing Arginine-HCl at 0, 50, or 150 mM all showed very low ISP. Histidine buffer at pH 6.5 showed a lower ISP than pH 5.7.This systematic study via orthogonal analyses demonstrated that subcutaneous ISP is significantly influenced by solution composition.

Using detailed transaction-level data from financial accounts, this paper shows that the revenues of small businesses and the consumption spending of their owners both decline by roughly 40% following the declaration of the national emergency in March 2020. However, through May 2020, the vast majority of this average decline in revenues is due to national factors rather than to variation in local infection rates or policies. Further, there is only a modest propensity for business owners to cut consumption in response to their individual business losses: Comparing owners in the same county but whose businesses operate in industries differentially impacted by local infections and state-level policies, we show that each dollar of revenue loss leads to a 1.6 cent decline in the consumption of the owner at this early stage of the pandemic. This limited passthrough appears to be explained by three factors: (1) the liquidity of households and businesses entering the crisis – consumption is twice as responsive for small business owners who operate with low liquidity; (2) emergency Federal programs – median account balances in both business and checking accounts decline in March but rebound in April and May when the transfer programs begin; (3) pandemic induced declines in the ability to spend on consumption – spending on travel, restaurants or personal services dropped dramatically.

The rise of Target Date Funds (TDFs) has moved a significant share of retail investors into contrarian trading strategies that rebalance between stocks and bonds so as to maintain age-appropriate portfolio shares. We show that i) TDFs actively rebalance within a few months following differential asset-class returns to maintain stable portfolio shares, ii), this rebalancing drives contrarian rebalancing flows across funds held by TDFs, iii) investors do not move funds into or out of TDFs to offset these flows, and iv) these flows impact the prices of stocks. Across otherwise similar stocks, those with higher (indirect) TDF ownership experience lower returns after higher market-wide performance, a results that holds when looking only at variation in TDF ownership driven by S&P index inclusion. Consistent with this price impact, the stock market exhibits more reversion at the monthly frequency during the recent TDF era. Together, our results suggest that continued growth in TDFs may affect return dynamics and the relation between stock and bond returns.

We develop a tractable dynamic model of credit markets in which lending standards and the quality of potential borrowers are endogenous. Competitive banks privately choose their lending standards: whether to pay a cost to screen out some unprofitable borrowers. Lending standards have negative externalities and are dynamic strategic complements: tighter screening worsens the future pool of borrowers for all banks and increases their incentives to screen in the future. Lending standards can amplify and prolong temporary downturns, affecting lending volume, credit spreads, and default rates. We characterize constrained-optimal policy which can generally be implemented as a government loan insurance program. When markets recover, they may do so only slowly, a phenomenon we call “slow thawing.” Finally, we show that limits on lending such as from capital constraints naturally incentivize tight lending standards, further amplifying shocks to credit markets. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Many firms want to target their customers with a sequence of marketing actions, rather than just a single action. We interpret sequential targeting problems as a Markov Decision Process (MDP), which can be solved using a range of Reinforcement Learning (RL) algorithms. MDPs require the construction of Markov state spaces. These state spaces summarize the current information about each customer in each time period, so that movements over time between Markov states describe customers’ dynamic paths. The Markov property requires that the states are “memoryless,” so that future outcomes depend only upon the current state, not upon earlier states. We propose a method for constructing Markov states from historical transaction data by adapting a method that has been proposed in the computer science literature. Rather than designing states in transaction space, we construct predictions over how customers will respond to a firm’s marketing actions. We then design states using these predictions, grouping customers together if their predicted behavior is similar. To make this approach computationally tractable, we adapt the method to exploit a common feature of transaction data (sparsity). As a result, a problem that faces computational challenges in many settings, becomes more feasible in a marketing setting. The method is straightforward to implement, and the resulting states can be used in standard RL algorithms. We evaluate the method using a novel validation approach. The findings confirm that the constructed states satisfy the Markov property, and are robust to the introduction of non-Markov distortions in the data.

This paper evaluates theoretical explanations for the propensity of households to increase spending in response to the arrival of predictable, lump-sum payments, using households in the Nielsen Consumer Panel who received $25 million in randomly distributed stimulus payments. The pattern of spending is inconsistent with models in which identical households cycle rapidly through high and low- response states as they manage liquidity, but is instead highly predictable by income years before the payment. Spending responses are unrelated to expectation errors, almost unrelated to crude measures of procrastination and self-control, significantly related to sophistication and planning, and highly related to impatience. (JEL D12, D14, D91, E21, H23)

Many transit agencies have developed measurements of pedestrian crowding in rail stations but lack clear standards for when crowding becomes a safety risk that justifies an operating or capital intervention. How frequent, consistent, or severe must congestion be before a capital improvement is warranted to mitigate a safety risk? How should agencies weigh severe but infrequent congestion against moderate but daily congestion? Adoption of such standards is a critical step for a transit agency in identifying and prioritizing safety risks and capital needs. The Washington Metropolitan Area Transit Authority (WMATA, or Metro) uses a variety of methods to measure pedestrian crowding at Metrorail stations on platforms, escalators, and stairs and through fare gates. WMATA has incorporated big data into its measuring of crowding in rail stations and has recognized that using demand on a typical weekday can mask important variations and issues in normal operations. The agency has relied on the Transit Capacity Quality of Service Manual (TCQSM) to establish the capacity of station circulation elements, but the manual’s existing measures do not address questions of the frequency and severity of overcrowding or of what levels of crowding warrant action or capital projects. Although peer agencies commonly use station capacity values consistent with the TCQSM, other agencies have developed specific guidelines for acceptable peak crowding duration and special event conditions. This paper summarizes WMATA’s analytic approaches, including the use of pedestrian microsimulations to derive volume-to-capacity ratios and level of service. The paper concludes by calling for clear standards that consider frequency, severity, and acceptable safety thresholds.

Using a proprietary dataset of the portfolio holdings of millions of US households, we document how agents who believe in different models of the world update their beliefs heterogeneously in response to a public signal. We identify households ex ante that hold different models of the world using political party affiliation (probabilistically inferred from zip code), and our public signal is the unexpected outcome of the US national election of 2016. Relative to Democrats, Republican investors actively increase the equity share and market beta of their portfolios following the election. The rebalancing is due to a small share of investors making large adjustments. We conclude that this behavior is driven by belief heterogeneity because of extensive controls for differential hedging needs or preferences, including detailed controls for age, wealth, income, state, and even county-employer fixed effects.

We evaluate the consistency of two methods for estimating the effect of an economic policy: i) asking people how the policy caused them to change their behavior (reported effects); ii) inferring this change using data on behavior and differences in treatment across people (revealed-preference estimates). Both methods are widely used to measure spending caused by increases in liquidity. Using Federal stimulus payments disbursed quasi-randomly in 2008, we find larger revealed-preference estimates of spending propensities for households who report greater spending responses, and the methods produce similar average propensities. But evidence is mixed on the relationship between spending propensities and liquidity.

The remaining potential in many mature fields in the Gulf of Mexico consists of smaller long-reach targets that require ever-more-accurate vertical and horizontal location for drilling precision. This is particularly true at the Lobster field in Ewing Bank, where, during the previous platform drilling campaigns, some midreach prospects were interpreted to have been missed due to mispositioning. Potential future drilling at the Lobster field would target primarily long-reach prospects in areas of significant geologic dip — increasing the risk of missing the prospects. This mispositioning risk could sometimes exceed the geologic risk, and it could have significant impact on the risked reserves and on the economics. Achieving the desired positioning accuracy requires the use of 3D seismic and anisotropic prestack depth migration with accurate velocity and anisotropy models. We have developed a case study of using a long offset walkaway checkshot and a geologic frame of reference to build a tilted transverse isotropy velocity model sufficiently accurate to support potential future drilling campaigns at the Lobster field.

We study a market for funding real investment where valuation—meaning investors devoting resources to acquiring information about future payoffs—creates an adverse selection problem. Unlike previous models, more valuation is associated with lower market prices and so greater returns to valuation. This strategic complementarity in the capacity to do valuation generates multiple equilibria. With multiple equilibria, the equilibrium without valuation is most efficient despite funding some unprofitable investments. Switches to valuation equilibria, valuation runs, look like credit crunches. A large investor can ensure the efficient equilibrium only if it can precommit to a price and potentially, only if subsidized.

Households in the Nielsen Consumer Panel were surveyed about their 2008 Economic Stimulus Payment. In estimates identified by the randomized timing of disbursement, the average household׳s spending rose by 10 percent the week it received a Payment and remained high cumulating to 1.5–3.8 percent of spending over three months. These estimates imply partial-equilibrium increases in aggregate demand of 1.3 percent of consumption in the second quarter of 2008 and 0.6 percent in the third. Spending is concentrated among households with low wealth or low past income; a household׳s spending did not increase significantly when it learned about its Payment., Sloan School of Management, Northwestern University (Evanston, Ill.). Kellogg School of Management, University of Chicago. Initiative for Global Markets, Northwestern University (Evanston, Ill.). Kellogg School of Management. Zell Center for Risk Research, Harvard University. Laboratory for Applied Economics and Policy

We develop a structural theory of beliefs and behavior that relaxes the assumption of time consistency in beliefs. Our theory is based on the trade-off between optimism, which raises anticipatory utility, and objectivity, which promotes efficient actions. We present it in the context of allocating work on a project over time, develop testable implications to contrast it with models assuming time-inconsistent preferences, and compare its predictions to existing evidence on behavior and beliefs. Our predictions are that (i) optimal beliefs are optimistic and time inconsistent; (ii) people optimally exhibit the planning fallacy; (iii) incentives for rapid task completion make beliefs more optimistic and worsen work smoothing, whereas incentives for accurate duration prediction make beliefs less optimistic and improve work smoothing; (iv) without a commitment device, beliefs become less optimistic over time; and (v) in the presence of a commitment device, beliefs may become more optimistic over time, and people optimally exhibit preference for commitment. This paper was accepted by Neng Wang, finance.

We evaluate the consistency of two methods for estimating the effect of an economic policy: i) surveying people to report the change in their behavior caused by the policy, ii) inferring this change using (reported) actual behavior and differences in treatment across people. Both methods have been widely used to measure propensities to spend. Using Federal stimulus payments disbursed quasi-randomly over time in 2008, we find greater revealed-preference estimates of spending by households reporting greater spending and the two methods produce similar estimates of average spending. But, counterfactually, reported preferences estimates are not higher for households with lower liquidity.

We measure the response of household spending to the economic stimulus payments (ESPs) disbursed in mid-2008, using special questions added to the Consumer Expenditure Survey and variation arising from the randomized timing of when the payments were disbursed. We find that, on average, households spent about 12-30% (depending on the specification) of their stimulus payments on nondurable expenditures during the three-month period in which the payments were received. Further, there was also a substantial and significant increase in spending on durable goods, in particular vehicles, bringing the average total spending response to about 50-90% of the payments. Relative to research on the 2001 tax rebates, these spending responses are estimated with greater precision using the randomized timing variation. The estimated responses are substantial and significant for older, lower-income, and home-owning households. We find little evidence that the propensity to spend varies with the method of disbursement (paper check versus electronic transfer).

Results for the solubilization of metals from biosolid- (BSL-) treated soils by simulated organic acid-based synthetic root exudates (OA mixtures) of differing composition and concentrations are presented. This study used two BSL-treated Romona soils and a BSL-free Romona soil control that were collected from experimental plots of a long-term BSL land application experiment. Results indicate that the solubility of metals in a BSL-treated soil with 0.01 and 0.1 M OA mixtures was significantly higher than that of 0.001 M concentrations. Differences in composition of OAs caused by BSL treatment and the length of growing periods did not affect the solubility of metals. There were no significant differences in organic composition and metals extracted for plants grown at 2, 4, 8, 12, and 16 weeks. The amount of metals extracted tended to decrease with the increase of the pH. Results of metal dissolution kinetics indicate two-stage metal dissolution. A rapid dissolution of metals occurred in the first 15 minutes. For Cd, Cu, Ni, and Zn, approximately 60–70% of the metals were released in the first 15 minutes while the initial releases for Cr and Pb were approximately 30% of the total. It was then followed by a slow but steady release of additional metals over 48 hours.

This year, the NBER Macroeconomics Annual celebrates its thirtieth volume. The first two papers examine China’s macroeconomic development. “Trends and Cycles in China's Macroeconomy” by Chun Chang, Kaiji Chen, Daniel F. Waggoner, and Tao Zha outlines the key characteristics of growth and business cycles in China. “Demystifying the Chinese Housing Boom” by Hanming Fang, Quanlin Gu, Wei Xiong, and Li-An Zhou constructs a new house price index, showing that Chinese house prices have grown by ten percent per year over the past decade. The third paper, “External and Public Debt Crises” by Cristina Arellano, Andrew Atkeson, and Mark Wright, asks why there appear to be large differences across countries and subnational jurisdictions in the effect of rising public debts on economic outcomes. The fourth, “Networks and the Macroeconomy: An Empirical Exploration” by Daron Acemoglu, Ufuk Akcigit, and William Kerr, explains how the network structure of the US economy propagates the effect of gross output productivity shocks across upstream and downstream sectors. The fifth and sixth papers investigate the usefulness of surveys of household’s beliefs for understanding economic phenomena. “Expectations and Investment,” by Nicola Gennaioli, Yueran Ma, and Andrei Shleifer, demonstrates that a chief financial officer's expectations of a firm's future earnings growth is related to both the planned and actual future investment of that firm. “Declining Desire to Work and Downward Trends in Unemployment and Participation” by Regis Barnichon and Andrew Figura shows that an increasing number of prime-age Americans who are not in the labor force report no desire to work and that this decline accelerated during the second half of the 1990s.

Functional gastrointestinal disorders (FGIDs) describe patients who present with symptoms that arise from the gastrointestinal (GI) tract yet have failed to be explained by a standard GI work-up. Somatic findings at midthoracic levels correspond to localized visceral dysfunction such as decreased peristalsis and vasoconstriction. The somatovisceral concept suggests that osteopathic manipulative treatment (OMT) provides relief by normalizing the autonomic tone. There are few reports in the literature that provide examples of successful treatment of FGID by OMT. This case describes a patient with postprandial nausea and vomiting who was successfully treated with OMT.

We do not have a good measure of the effects of fiscal policy in a recession because the methods that we use to estimate the effects of fiscal policy—both those using the observed outcomes following different policies in aggregate data and those studying counterfactuals in fitted model economies—almost entirely ignore the state of the economy and estimate “the” government multiplier, which is presumably a weighted average of the one we care about—the multiplier in a recession—and one we care less about—the multiplier in an expansion. Notable exceptions to this general claim suggest this difference is potentially large. Our lack of knowledge stems significantly from the focus on linear dynamics: vector autoregressions and linearized (or close-to-linear) dynamic stochastic general equilibrium (DSGE) models. Our lack of knowledge also reflects a lack of data: deep recessions are few and nonlinearities hard to measure. The lack of statistical power in the estimation of nonlinear models using aggregate data can be addressed by exploiting estimates of partial-equilibrium responses in disaggregated data. Microeconomic estimates of the partial-equilibrium causal effects of a policy can discipline the causal channels inherent in any DSGE model of the general equilibrium effects of policy. Microeconomic studies can also provide measures of the dependence of the effects of a policy on the states of different agents, which is a key component of the dependence of the general-equilibrium effects of fiscal policy on the state of the economy. (JEL E12, E13, E32, E62, H50)

We document a large increase in the cyclicality of the incomes of high-income households, coinciding with the rise in their share of aggregate income. In the U.S., since top income shares began to rise rapidly in the early 1980s, incomes of those in the top 1 percent of the income distribution have averaged 14 times average income and been 2.4 times more cyclical. Before the early 1980s, incomes of the top 1 percent were slightly less cyclical than average. The increase in income cyclicality at the top is to a large extent due to increases in the share and the cyclicality of their earned income. The high cyclicality among top incomes is found for households without stock options; following the same households over time; for post-tax, post-transfer income; and for consumption. We study cyclicality throughout the income distribution and reconcile with earlier work. Furthermore, greater top income share is associated with greater top income cyclicality across recent decades, across subgroups of top income households, and, in changes, across countries. This suggests a common cause. We show theoretically that increases in the production scale of the most talented can raise both top incomes and their cyclicality.

Mandibular repositioning appliance (MRA) therapy for snoring and obstructive sleep apnea (OSA) is an accepted treatment option for patients with mild to moderate disease. A recent comprehensive review of oral appliance therapy reported that patients with mild to severe OSA had a 52% chance of having an apnea-hypopnea index (AHI) < 10/h with a mandibular repositioning appliance.1 This rate of efficacy was not measurably better than that found in an earlier comprehensive literature review,2 despite improvements in the quality of the research studies and the introduction of titratable MRAs. In general, the adjustable MRA is initially set at 50% to 75% of maximum mandibular protrusion. The appliance is further advanced until symptoms improve or the maximum tolerated protrusion is reached. Overnight monitoring is usually done to determine the amount of objective improvement in apnea severity with MRA treatment. Despite the widespread use of titratable appliances, efficacy rates are not significantly better than those of fixed position appliances.1,2 Previous research has evaluated whether overnight titration of mandibular advancement during polysomnography could be used to initiate MRA therapy in a fashion similar to the titration of nasal continuous positive airway pressure (CPAP). The first study of overnight titration used an appliance that was removed from the patient's mouth and adjusted manually.3 Other titration studies have used a temporary appliance that can be adjusted either by awakening the patient4 or without awakening the patient.5,6 The temporary appliance was advanced either manually after removal of the temporary appliance,4 by a hydraulic system,5 or by remote control of a motorized system.6 However, results of these studies were mixed in terms of predicting the amount of advancement needed for successful MRA therapy. Furthermore, overnight titration of an MRA remains an experimental approach, and the technology for remote-controlled advancement is not widely available. Another method for appliance titration consists of clinical titration of the device to symptom resolution or to maximum tolerated advancement, with the addition of overnight home monitoring to determine objective improvement. The addition of home monitoring may provide data of an incomplete response that could allow further advancement to take place prior to outcome polysomnography (PSG). In a study of 40 patients using this approach, 64% of subjects had a complete response (AHI < 10/h with resolution of symptoms).7 Although this is a better success rate than in most studies of MRA therapy, many patients in this study were insufficiently treated despite an intensive clinical titration protocol. We evaluated a simple clinical protocol consisting of incremental advancement of an MRA by the patient to the point of good symptom control, followed by a titration PSG with the opportunity to further advance the appliance if needed. This titration PSG allowed for further advancement of the MRA during the night if the AHI remained high. The goal of the study was to determine if patients with an elevated AHI, despite the use of a clinically optimized MRA, could achieve better results with additional titration during the outcome PSG.

This paper evaluates theoretical explanations for the propensity of households to increase spending in response to the arrival of predictable, lump-sum payments, using households in the Nielsen Consumer Panel who received 25 million in randomly-distributed stimulus payments. The pattern of spending is inconsistent with models in which identical households cycle rapidly through high and low response states as they manage liquidity, but is instead highly predictable by income years before the payment. Spending responses are unrelated to expectation errors, almost unrelated to crude measures of procrastination and self-control, significantly related to sophistication and planning, and highly related to impatience.

The twenty-ninth edition of the NBER Macroeconomics Annual continues its tradition of featuring theoretical and empirical research on central issues in contemporary macroeconomics. Two papers in this year’s issue deal with recent economic performance: one analyzes the evolution of aggregate productivity before, during, and after the Great Recession, and the other characterizes the factors that have contributed to slow economic growth following the Great Recession. Another pair of papers tackles the role of information in business cycles. Other contributions address how assumptions about sluggish nominal price adjustment affect the consequences of different monetary policy rules and the role of business cycles in the long-run decline in the share of employment in middle-wage jobs. The final chapter discusses the advantages and disadvantages of the elimination of physical currency.

This paper evaluates theoretical explanations for the propensity of households to increase spending in response to the arrival of predictable, lump-sum payments, using households in the Nielsen Consumer Panel who received $25 million in Federal stimulus payments that were distributed randomly across weeks. The pattern of spending is inconsistent with models in which identical households cycle through high and low response states as they manage liquidity. Instead, the propensity spend is a persistent household trait. This trait is unrelated to expectation errors, almost unrelated to crude measures of procrastination and self-control, moderately related to measures of sophistication and planning, and highly related to a measure of impatience.

Under the Economic Growth and Tax Relief Reconciliation Act of 2001, most U.S. taxpayers received a tax rebate between July and September, 2001. The week in which the rebate was mailed was based on the second-to-last digit of the taxpayer's Social Security number, a digit that is effectively randomly assigned. Using special questions about the rebates added to the Consumer Expenditure Survey, we exploit this historically unique experiment to measure the change in consumption expenditures caused by receipt of the rebate and to test the Permanent Income Hypothesis and related models. We find that households spent about 20-40 percent of their rebates on non-durable goods during the three-month period in which their rebates were received, and roughly another third of their rebates during the subsequent three-month period. The implied effects on aggregate consumption demand are significant. The estimated responses are largest for households with relatively low liquid wealth and low income, consistent with liquidity constraints.