Printer Friendly

AIDS testing: an economic assessment of evolving public policy.

AIDS TESTING: AN ECONOMIC ASSESSMENT OF EVOLVING PUBLIC POLICY

Should laissez faire prevail as to the private-market supply of the AIDS antibody test? Applying a recent theorem from the economics of property rights, this paper determines that the answer is negative, and shows that the optimal policy regarding the AIDS antibody test differs according to whether individuals are at low risk or high risk. Next, using the same economic theory, this paper finds that rules guaranteeing strict confidentiality of the AIDS test result are unjustified. They also are unjustified on traditional legal grounds.

I. INTRODUCTION

The AIDS antibody test was licensed in Spring 1985. It can identify people who have been infected with the AIDS (HIV) virus and are capable of spreading it, even though they don't have AIDS. The introduction of the AIDS antibody test raises issues in the economics of property rights. This paper considers these issues and the efficient government's response.

First, the paper asks whether laissez faire should prevail regarding the private-market supply of the AIDS antibody test. Applying a recent theorem from the economics of property rights, the answer is negative. The optimal policy differs according to whether individuals are at low risk or high risk to AIDS. For low-risk workers, the analysis demonstrates that an efficient government would, in general, tax the test to force these workers to internalize their negative pecuniary impact on the perceived quality of high-risk workers. A form of this tax already appears to be in place. For relatively high-risk workers, the analysis shows that governments would provide subsidies to nonprofit organizations that test and counsel them. This also appears to be the case.

Next, this paper assesses a crucial issue with respect to AIDS testing, the legal and economic effects of rules guaranteeing strict confidentiality of the AIDS test result. Using the same economic theory, allowing individuals to suppress antibody-positive test results is shown to be unjustified on economic grounds. It is also unjustified on traditional legal grounds. The analysis suggests that the public-spirited doctor of an antibody-positive person should be allowed to decide whether to inform the person's sex partners and health care team. Otherwise, a conscientious state official should make this decision. Such policies currently are being developed across the United States.

II. THE ECONOMIC EFFECTS OF A PRIVATE-MARKET SUPPLY OF THE AIDS TEST

AIDS testing has spread far beyond blood banks, where it is required of blood donors. Most states in the U.S. and many local governments lend financial support to the AIDS testing centers of nonprofit organizations of individuals at high risk to AIDS.(1) These centers commonly offer members a free test, mandatory counseling, and confidentiality of the AIDS test result.

In contrast, governments have shown a great deal of resistance to allowing the private for-profit sector to provide AIDS antibody tests freely to the relatively low-risk heterosexual population. Indeed, several states and localities have gone so far as to prohibit employers from using an AIDS antibody test to determine suitability for all employment.(2) Also, in fall 1985 a nationwide, for-profit company, responding to a growth in demand for AIDS testing (largely from the relatively low-risk heterosexual population), proposed to increase greatly the private availability of the AIDS antibody test. At least one governmental body, the Los Angeles City Council, responded negatively, directing five different city agencies to investigate the company.(3) Similarly, in April 1988, after over a two-year delay, private companies planning to sell home testing kits for the AIDS antibody, aimed for marketing to groups at low risk to AIDS, were blocked by the Federal Drug Administration.

Can economic theory rationalize our government's simultaneous encouragement of AIDS testing of high-risk groups while discouraging the private testing of low-risk groups?

General Assumptions

Assume, first, that individuals who learn they've been exposed to the AIDS virus cannot use the tort liability system to collect from the carriers who infected them.(4) Second, assume (until section III) that all results of AIDS antibody tests are public information, freely offered to all interested parties. Third, assume that high-risk individuals who do not take the test can costlessly imitate low-risk individuals, perhaps with the help of the government.(5) In other words, the private cost of distinguishing an untested low-risk from an untested high-risk individual always exceeds the private returns. Thus, only through testing is the private separation of high-risk and low-risk individuals possible. The analysis differs from a traditional screening analysis (as exemplified by Spence [1973]), both because testing, the method of separation in this paper, informs the test-taker as well as the public, and because testing has possibly negative effects on the wealth of any test-taker.

Now, the question is this: Should laissez faire prevail regarding the private-market supply of the AIDS antibody test?

Considering a restaurant example, let restaurants fall into two potential categories: the first group has low-risk workers who privately know they likely are unexposed to the AIDS virus; the second, high-risk workers who privately know they likely are exposed to the AIDS virus. If customers could not discern whether a particular restaurant employed predominantly low-risk or high-risk workers and no AIDS test was initially offered, this initial situation would be one in which private property rights--in this case to the differing workers' unique products--were unassigned. Whether low-risk or high-risk, all workers would be untested and receive the same "pooled" wage. Restaurants and their customers would consume out of the common pool of workers.

Subsequent to the availability of the AIDS antibody test, the actual equilibrium will not involve this level of communality. Some restaurant workers will separate themselves by taking the test, thereby converting some of the common property of the other workers into their own private property. Others will avoid taking the test, thereby restraining the conversion of common to private property.

The Applicable Theorem

A recent theorem from the economics of property rights considers this situation. When there are positive private costs of acquiring initial private rights to previously valuable common property, rational unrestrained individuals will devote more than the socially optimal amount of resources to converting that property to private ownership. Such individuals will ignore the loss in benefits that others would otherwise receive from the previously common property. The theorem's corollary says that other rational unrestrained individuals will also devote too many resources to keeping otherwise private property common. Such individuals will ignore the loss in benefits that others would otherwise receive from the privatization of common property.(6)

This theorem implies a role for the efficient government when private property is initially unassigned. The efficient government acts to eliminate the socially wasteful utilization of resources for such solely redistributional purposes. In the first case, where rational individuals devote too many resources to converting previously valuable common property to private property, either the efficient government establishes certain initially unassigned property as common property administered by the government, or it taxes the acquisition of previously unassigned property. In the latter situation, for example, the efficient government outlaws--that is, places a 100 percent tax on--the crimes of blackmail and extortion, which represent an unambiguously wasteful use of resources. In the second case, where rational individuals devote too many resources to keeping otherwise private property common, the theorem's corollary says that the efficient government subsidizes the creation of the private property.

Applying the Theorem: Illustrative Examples

In the restaurant example, AIDS-free workers initially are confused with AIDS-exposed workers. Suppose all customers are willing to pay $1 more for a meal in a restaurant whose workers have tested negative for the AIDS antibody than for a meal in a restaurant employing only high-risk workers.(7) Then the fortunate customers of restaurants that happen to employ low-risk workers are not paying for this higher-valued service, but are enjoying its benefits. In economic terms, these customers are reaping a windfall, an unexpected consumer surplus. The customers of the other restaurants are bearing a corresponding loss.

Now suppose private for-profit firms introduce the AIDS virus test for a nominal fee. That is, there is a small overhead cost to demonstrating one tests negative for the AIDS antibody. Does this additional private test supply make society better off?

The following illustrative equilibria all assume that customers have fixed premia for antibody-negative workers over other workers, producers have constant costs, and that the two types of workers have homogeneous preferences. These simplifying assumptions are dropped for the general case described at the end of this section. Low-Risk Individuals: The First Extreme Case. The applicable theorem implies that low-risk individuals will devote too many resources to taking the AIDS test so as to demonstrate that they're not high-risk individuals. Low-risk individuals gain monetarily at the cost of high-risk individuals and should be correspondingly taxed for taking the AIDS antibody test.

Consider the restaurant example--specifically, the case where the number and type of restaurant customers and workers remain unchanged. In the new competitive equilibrium, there is a higher price of meals in restaurants with workers who have tested negative and a lower price in restaurants whose workers have not. For example, the price of a meal in restaurants demonstrating negative test results may rise by fifty cents, and, in other restaurants, fall by fifty cents. Per-meal wage costs of negatively-tested workers correspondingly rise by fifty cents, while those of other workers fall by fifty cents.

Those workers--and only those workers--most likely risk-free of the AIDS virus will take the test. Workers who think they're likely to fail the test will avoid it, accepting the lower wage. In this case, the increased supply of testing does not alter the surplus of consumers in total. While customers of the low-risk restaurants now pay a higher price for a previously higher-valued meal, the others now pay lower prices to compensate them for their now-acknowledged, lower-valued meals.

Here, AIDS antibody testing merely enables low-risk workers to earn higher wages at the expense of high-risk workers. Such low-risk workers who choose to take the test impose a redistributive pecuniary externality upon high-risk workers. Low-risk workers do not take into account the loss of surplus to those people (the high-risk workers) who previously benefited from the undefined situation.

In this case, then, the gains from the test are soley redistributional, for all workers are providing the same services as before! The redistributional benefits to low-risk workers are a socially wasteful reason for the private provision of the costly AIDS antibody test.

Applying the theory of the efficient government's role when private property is initially unassigned to this case, the efficient government would prohibitively tax the private acquisition of the previously unassigned property. That is, it would outlaw the private AIDS antibody test. Low-Risk Individuals: The Second Extreme Case. Next, consider an alternative, extreme case where (1) all existing restaurant customers are indifferent between food handled by the two types of workers, and (2) the introduction of AIDS antibody testing increases the total number of customers by adding a new group of sensitive customers, all of whom place a $1 premium on food handled by antibody-negative workers. The second group of customers (who previously chose not to eat out), now go out to new restaurants charging $1 per meal more than the old restaurants and paying $1 per meal more in wages to workers boasting negative test results. In this case, the increase in the demand price for eating in restaurants, representing the private value of providing the test, is also the social value of the test. Here, the test induces no reduction in the total demand for the products of workers in the previously existing restaurants and thus no redistributional effect away from other restaurant workers.

In this case, the efficient government would allow a laissez faire, competitive supply of AIDS testing. Low-Risk Individuals: The More Realistic, Intermediate Case. Reality lies between these two extremes. To accommodate it, an efficient government would place a tax on the test to force low-risk workers to internalize their negative impact on the perceived quality of high-risk workers. That is, the efficient government would tax away the low-risk workers' redistributional gain from taking the AIDS antibody test. High-Risk Individuals. At the same time, the public would benefit if the high-risk workers would take the test and, if found antibody-positive, appropriately modify their behaviors. However, all high-risk workers rationally choose to avoid the test altogether, moving to occupations in which test outcomes are less important, accepting lower wages in the process; or to remain at their original jobs, inefficiently imitating those low-risk workers who have an aversion to the test. That is, high-risk individuals avoid the antibody test--despite its generally positive real value to them as well as society--because of the high likelihood of a resulting wage reduction and consequent redistributive increase in the wealth of others. To counter this overdevotion of resources by the beneficiaries of common property to keeping their property common, the flip side of the Thompson result applied above, an efficient government would subsidize the testing of these individuals.

Applying the Theorem: The General Case

The extreme cases can be generalized to one in which (1) all restaurant customers, both pre-existing and previously extramarginal, place a premium on dining in restaurants boasting antibody-negative workers, customers having individually diminishing marginal utilities (decreasing demand prices) for such services; and (2) workers suffer an increasing cost (a rising supply price) of taking the AIDS antibody test. Again, let the equilibrium net nonpecuniary return to an antibody-negative result be $1. This equilibrium is comprised of three groups of workers. The highest wage group, those workers whose test results successfully demonstrate their antibody negative, earn wages of $1 more per meal than the other restaurant workers. The group receiving the lowest wage offers take the test and, unfortunately, learn of their antibody positivity. We can assume that these workers refuse the low wage offers and, subsequently, move to other kinds of jobs or retire. The third group is comprised of a mixture of low-risk workers who choose not to take the test because they have a relatively high aversion to taking such tests, and those high-risk workers choosing to imitate them.

In general, then, some of the high-risk workers (all of whom are in the third group described above), being beneficiaries of common property consumption and able to maintain this status by avoiding the AIDS antibody test even though the private nonredistributive benefits exceed the costs, substantially underinvest in taking the test. And at the same time, some of the low-risk workers (those in the first group), being beneficiaries of conversion of common to private property and able to achieve such conversions by testing even though the private nonredistributive value of the test is far below the costs of the test, substantially overinvest in taking the test.

Summary

As the theory would have it, current policies provide a mixture of redistributive government monitoring of private for-profit AIDS testing and counseling clinics, which treat mostly low-risk individuals, and government subsidies to not-for-profit clinics, which typically test and counsel high-risk individuals. With the recent growth in demand for AIDS antibody testing, largely from the relatively low-risk heterosexual population, the once-banned private for-profit clinics are coming forward to supply the test. These providers remain unimpeded, but only so long as they continue to assure government officials that their test results are not being misused.(8) Rather than directly tax the test, government officials choose to monitor closely private AIDS testing. At the same time, nonprofit organizations are provided government subsidies to test and counsel their relatively high-risk populations.

III. THE LEGAL AND ECONOMIC EFFECTS OF AIDS TEST CONFIDENTIALITY

Most AIDS testing clinics across the nation, whether public or private, protect the confidentiality of the test result. In California, for example, under the strict "Agnos Law," which makes it unlawful for a physician to disclose an AIDS test result to any third party without the patient's written consent, the patient and blood sample may be identified only by number. No name or other personal identification need be attached to an individual's AIDS antibody test.

Disease Confidentiality and the Tort System

Confidentiality would make economic sense if AIDS victims could be practically made to pay for the injuries they impose on others. With other less-threatening diseases, the tort liability system promotes this result. That is, a person who knowingly inflicts injury against another has in legal terms committed a tort and can be held legally responsible for the damages. For example, in recent years cases have been won by plaintiffs contracting genital herpes from partners who knew they had the disease, but did not disclose it.(9) In theory, a well-functioning tort liability system takes the place of all economic policy as regards testing for a disease.

However, the tort liability system breaks down, in general, against a person with AIDS. An AIDS victim who infects another will go bankrupt (or even die) before being sued for the severe damage that person creates.(10) Also, for communicable and sexually transmitted diseases, it is extremely difficult for an infected person to prove who gave that person the disease. In addition, litigants for AIDS face at least an average five-year time lag between exposure to the virus and development of the disease.(11) (In contrast, the herpes incubation period is at most two weeks.) Hence, the granting of confidentiality to an individual who tests antibody-positive is not warranted by the usual argument permitting confidentiality. A real externality is present. Yet the subsequently infected victim has no practical legal recourse.

Furthermore, laws making it illegal for a physician to disclose a positive AIDS test result deviate from long-standing medical practice. In general, the safety of the public has long been held to supersede individuals' rights to privacy. Indeed, state health agencies require physicians to report cases of certain communicable diseases as well as child and elder abuse. Also, prior to recent laws, physicians routinely notified cohabiting partners of patients diagnosed to have sexually transmitted diseases.

Today in many states, when a person tests positive for syphilis or gonorrhea, health authorities will ask the names of people with whom that person has been intimate. Then, without mentioning the name of the carrier, health authorities will confidentially notify those people who may have contracted the disease, and recommend that they come in to be tested.(12)

Unlike AIDS, however, syphilis and gonorrhea have very short incubation periods and can be completely cured by current medical procedures. These differences also must be considered in devising an optimal economic policy.

Optimal Policy

In the case that the tort system works and a disease is not extremely serious--such as in the herpes example--we should, as we do, grant the carrier's strict confidentiality.

But when the tort system malfunctions, the granting of confidentiality of the person's status depends upon whether there exists an economically rational basis for that status or whether others will misuse the information. Will the person's status have a real, significant economic effect upon others? Will others use the information simply to redistribute from the person?

In the case that there is no rational basis for treating the person differently, and the person could be labeled differently only to enable some group to redistribute wealth from this less-powerful person, confidentiality should be allowed. Here, the granting of confidentiality staves off solely (in economic terms) "rent-seeking" individuals.

In contrast, when the tort system malfunctions and the person's status could have a significant economic effect on others, confidentiality would allow a tested carrier freely to imitate untested individuals, a situation which we have already derived to be inefficient. Here, strict confidentiality should in general not be allowed.

Hence, in the case of the AIDS disease, because of the inadequacy of the tort liability system and its sufficiently serious, communicable nature, strict confidentiality is generally undesirable.

With AIDS, the decision to breach confidentiality should be turned over to the carrier's knowledgeable, public-spirited doctor. Ideally, the doctor would weigh the carrier's disutility for exposure against the effect of others' use of the carrier's test outcome. If the carrier's spouse or health care team would misuse the information, e.g., solely to persecute the carrier, the doctor should maintain the carrier's confidentiality. If not, the carrier's doctor should selectively divulge the information. If the carrier's doctor refuses to make the decision, a conscientious state official should do so.

Current proposals support this view. Pressure to modify strict confidentiality is building across the nation. Beginning January 1989, California doctors were granted immunity from prosecution if they inform other medical personnel treating an HIV-positive patient, as well as sexual and needle-sharing partners, about HIV exposure (without revealing the source of the exposure). Also, while leaving the final decision to states, the U.S. Centers for Disease Control recommends the notification of the antibody-positive person's sex partners and health care team. Last but certainly not least, about a dozen states now require that positive tests be reported to state authorities.

REFERENCES Alexander, L.A. "Liability in Tort for the Sexual Transmission of Disease, Genital Herpes and

the Law." Cornell Law Review, November 1984, 101-40. Barzel, Y. "Optimal Timing of Innovations." Review of Economics and Statistics, August 1968,

348-55. Castagliola, D. and A.M. Downs. "Incubation Time for AIDS," Nature, August 1987, 582. Corcoran, J. C. "Customer Preference and the Bona Fide Occupational Qualification." Boston

College Law Review, December 1982, 256-66. Dalton, J. "The Consequences of an Uninformed Menage a Trois Extraordinaire: Liability to

Third Parties for the Nondisclosure of Genital Herpes Between Sexual Partners." Saint Louis

University Law Journal, April 1985, 787-815. Gordon, H.S. "The Economic Theory of a Common Property Resource: The Fishery." Journal

of Political Economy, April 1954, 124-42. Haddock, D. "First Possession Versus Optimal Timing: Limiting the Dissipation of Economic

Value." Washington University Law Quarterly, Fall 1986, 775-92. Los Angeles Times. "Articles Minimizing Risk of AIDS Assailed by Koop." February 20, 1988,

Part I, 2. Reidinger, P. "Negligent Sex: Herpes Victims Sue Their Partners." American Bar Association

Journal, April 1987, 1. Ricklefs, R. "Wiped Out: AIDS Victims Find That a Death Sentence Leads First to Poverty."

Wall Street Journal, August 5, 1987, 1. Schachter, V. "AIDS in the Workplace: Legal Issues Facing the Private Sector Employer." Legal

Backgrounder, Washington Legal Foundation, December 18, 1987. Schlei, B. L. and P. Grossman. Employment Discrimination Law. Washington, D.C.: Bureau of

National Affairs, 1976, 290. Spence, A. Michael. "Job Market Signalling." Quarterly Journal of Economics, August 1973,

355-74 Thompson, E. A. "The Optimal Role of Government in a Competitive Equilibrium with Transaction

Costs," in American Re-Evolution, Papers and Proceedings, edited by R. Auster and B.

Sears. Tucson, Arizona; Department of Economics, University of Arizona, 1977, 9-21. U.S. Centers for Disease Control, AIDS: Recommendations and Guidelines, Atlanta, Georgia,

1987a, 9. U.S. Centers for Disease Control. "The History of Patient Interviewing and Sex Partner Referral

In The Control of Sexually Transmitted Diseases." Recommended Additional Guidelines for

HIV Antibody Counseling and Testing in the Prevention of HIV Infection and AIDS, Atlanta,

Georgia, April 30, 1987b, App. IV, 3. Winterscheidt, R. A. "Employment Discrimination: Is Customer Preference a Bona Fide

Occupational Qualification?" University of Kansas Law Review, Fall 1982, 183-99. (*)Associate Professor, College of Business Administration, California State Polytechnic University, Pomona. I am grateful to Peter Aronson, Tom Borcherding, Gordon Tullock and an anonymous referee for helpful comments. (1)According to U.S. Surgeon General C. Everett Koop, groups at high risk to AIDS are homosexual males and intravenous drug abusers; see the Los Angeles Times [1988]. (2)See Schacter [1987], especially pages 5-6. (3)For a fee, the company would provide the test, certify with an identification card that a person had tested antibody-negative, and counsel clients about how to avoid AIDS. Council members expressed concern for people receiving false-positive test results. (While a multi-test regimen has largely removed the problem of false-positive results, researchers at Smith, Kline & French Laboratories announced in February 1988 an AIDS antibody test that virtually eliminates such results.) In addition, some Councilmen said the potential company smacked of "opportunism," and was exploiting the public's fear of AIDS. (4)Section II of this paper rationalizes this assumption. (5)For example, various local ordinances across the U.S. grant job-discrimination protection for homosexuals, effectively prohibiting private employers from inquiring of job applicants and employees as to their sexual orientation.

A general point of this paper, about to be elaborated, is that government policy helps generate labor market efficiency by preventing some of the more desirable types of workers from privately separating themselves from a common pool.

Note that the government may still find it very easy--and this is assumed to be the case--to separate high-risk from low-risk workers, in that high-risk workers are not subjecting themselves to the possibility of lower wages or prices when dealing with the government.

The problem of an efficient antidiscrimination policy toward high-risk workers is treated with the above highly simplified assumptions in order to concentrate the main discussion on the problem of optimalf policy towards AIDS testing. (6)This theorem is presented and elaborated in Thompson [1977]; see especially pages 9-10, 21. Thompson's result differs from the classic Marshallian "competitive overfishing" result presented by Gordon [1954], which also treats some rent-seeking activities involved with a common-pool asset. In the standard analysis, there is an overly-copied early exploitation of the asset relative to a perfectly optimal exploitation path. An optimum is achievable only with generally costly policies, such as an initial assignment of private property or a complex time-varying tax on relatively early property acquisitions. In Thompson's analysis, there are too many resources devoted to making otherwise common property private. Rational unrestrained individuals, by ignoring others' returns from the common-pool asset, will always see a private value that is greater than the social value of making otherwise common property private. Thompson's analysis correspondingly differs by supplying a simple, static role for the efficient government in this situation. Rather than implying either an idealistic, generally too costly, initial creation of private property or a similarly idealistic, intertemporally variable tax on exploiting the common, Thompson's result implies a simple static tax on the conversion of property from common to private use.

For example, take the case of the introduction of private titles to an initially common land parcel recently discussed by Haddock [1986]. Haddock first points out that wasteful rent-seeking activities result from a first-come, first-serve competition for private titles to the land, and then goes on to suggest initial government auctions or private monopolies in the absence of problems arising from innovation. In contrast, Thompson would first point out that unfettered individuals, even natural monopolists, by ignoring other individual's returns from the parcel as a common, see an overhigh net private return to creating a private title to the land. Thompson then would go on to argue for permanent taxes on acts associated with the privatization of the land, such as taxes on deed filling, fence building, and rent collecting. As in the following discussion, an efficient government in Thompson's analysis would take all individuals' utilities into account in evaluating an assertion of private property rights.

Thompson's claim also differs from Barzel's [1968] analysis is that it does not apply to innovative activity. (7)Differences in the predictability of different AIDS antibody tests and in the predictability of the same test on different populations do not alter the fact that customers place a premium on workers who test negative for the AIDS antibody. When the test becomes more imperfect, the price differential decreases.

For the same reason, uncertainty arising from a period between AIDS exposure and test dectection--the so-called "window of vulnerability"--does not change the basic analysis.

Pertinent to the restaurant application, Los Angeles Times polls in 1985 and 1987 report a fairly stable one-fifth of the U.S. population affirmatively answered the question, "Can people catch AIDS from eating food which as been handled by someone who has AIDS?" Also, a November 1987 Gallup poll reports that 26 percent of Americans relate the spread of AIDS to food handling or preparation. Yet the U.S. Centers for Disease Control reports no instances of AIDS transmission by food-service workers [1987a, 9].

The application is also supported by recent court decisions allowing employers exceptions to the 1964 Civil Rights Act in cases where evidence demonstrates that (a) customers prefer certain types of workers, and (b) a business would be undermined by hiring certain types of workers. For examples, see Corcoran [1982], Schlei and Grossman [1976, 290], and Winterscheidt [1982].

Finally, while the paper assumes all behavior is voluntary and responsive to effective consumer demand, nowhere is discrimination in the workplace assumed. Laws against discrimination in the labor market cannot compel customers to frequent certain establishments and not others. Hence, the 1987 U.S. Supreme Court decision that protects people with contagious diseases (such as tuberculosis and possibly AIDS) against job discrimination is inapplicable. (8)Discussion with an owner of Medical Screening Services, a private firm that provides the AIDS antibody test and counseling in clinics throughout Southern California. (9)See Alexander [1984], Dalton [1985], and Reidinger [1987]. (10)"Before AIDS kills people, it often makes them paupers," Ricklefs [1987]. (11)The U.S. Centers for Disease Control reports a five-year mean average AIDS incubation period. In contrast, recent U.S. and U.K. studies of people contracting AIDS from blood transfusions (whose dates are known with precision) indicate a mean incubation period of eight years; for adult men, it was five-and-one-half years, and for adult women, nearly nine years. Other studies find a mean incubation period as long as fifteen years. This issue is considered by Castagliola and Downs [1987]. (12)Fragmentary data from two states developing such "contact tracing" of sex partners of AIDS-positive individuals indicate the procedure can uncover other antibody-positive individuals, according to the U.S. Centers for Disease Control [1987b].
COPYRIGHT 1989 Western Economic Association International
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Thompson, Velma Montoya
Publication:Economic Inquiry
Date:Apr 1, 1989
Words:4955
Previous Article:First-price common value auctions: bidder behavior and the "winner's curse."
Next Article:Coaching team production.
Topics:

Terms of use | Copyright © 2017 Farlex, Inc. | Feedback | For webmasters