Appendix J describes what would be involved in applying such techniques to policy decisions about polygraph screening. We were not asked to do a formal policy analysis, and we have not done so. Considering the advantages and disadvantages of quantitative benefit-cost analysis, we do not advocate its use for making policy decisions about polygraph security screening.
The scientific basis for estimating many of the important parameters required for such an analysis is quite weak for supporting quantitative estimation. Moreover, there is no scientific basis for comparing on a single numerical scale some of the kinds of costs and of benefits that must be considered. Reasonable and well-informed people may disagree greatly about many important matters critical for a quantitative benefit-cost analysis e.
When social consensus appears to be lacking on important value issues, as is the case with polygraph screening, science can help by making explicit the possible outcomes that people may consider important and by estimating the likelihood that these outcomes will be realized under specified conditions. With that information, participants in the decision process can discuss the relevant values and the scientific evidence and debate the tradeoffs.
Given the state of knowledge about the polygraph and the value issues at stake, it seems unwise to put much trust in attempts to quantify the relevant values for society and calculate the tradeoffs among them quantitatively see National Research Council, b. However, scientific research can play an important role in evaluating the likely effects of different policy options on dimensions of value that are important to policy makers and to the country.
The above discussion considered the tradeoffs associated with polygraph testing in employee security screening situations in which the base rate of the target transgressions is extremely low and there is no specific transgression that can be the focus of relevant questions on a polygraph test.
The tradeoffs are different in other applications, and the value of polygraph testing should be judged on the basis of an assessment of the aspects of the particular situation that are relevant to polygraph testing. Because of the specific considerations involved in making decisions for each application, we have not attempted to draw conclusions about other applications.
Here, we note some of the important ways in which polygraph testing situations differ and some implications for deciding whether and how to use polygraph testing. A critically important variable is the base rate of the target transgressions or, put another way, the expected likelihood that any individual potential examinee is guilty or has the target information. We have already discussed the effects of base rate on the tradeoffs involved in making decisions from polygraph tests and the way the use of polygraph testing as an aid to decision making becomes drastically less attractive as the base rate drops below a few percent.
The costs of false positive and false negative errors are also important to consider in making policy choices. Consider, for example, the difference between screening scientists employed in the DOE laboratories and preemployment screening of similar scientists.
False positives are likely to cost both government and examinee less in preemployment screening because the people who test positive have not yet been trained in the laboratories and do not yet possess critical, specialized skills and national security information. The costs of false positives also vary across different preemployment screening applications.
For example, these costs are likely to be greater, for both the government and the potential employee, if the job requires extensive education, training, or past experience, because it is harder for the employer to find another suitable candidate and for the applicant to find another job. Thus, denying employment to a nuclear physicist is probably more costly both to the government and the individual than denying employment to a prospective baggage screener.
When false positive errors have relatively low cost, it makes sense to use a screening test with a fairly suspicious threshold. The costs of false negative errors rise directly with the amount of damage a spy, saboteur, or terrorist could do. Thus, they are likely to be greater in preclearance screening in relation to the sensitivity of the information to which the examinee might gain access.
This observation suggests that if polygraph testing is used for such screening, more suspicious thresholds make the most sense when a false negative result is a major concern. The incentive to use countermeasures is also greater when the cost of a false negative result is greater. Thus, the possibility of effective and undetectable polygraph countermeasures is a more important consideration in very high-stakes screening situations than in other applications.
Another important factor is whether or not the situation allows for asking questions about specific events, activities, places, and so forth. Theory and limited evidence suggest that polygraph testing can be more. In addition, if the target answers to these questions are known only to examiners and to the individuals who are the targets of the investigation or screening, it is possible to use concealed information polygraph test formats or to use other tests that rely on orienting responses, such as those based on brain electrical activity.
Thus, polygraph testing in general and concealed information tests either with the polygraph or other technologies are more attractive under these conditions than otherwise. Employee security screening in the DOE laboratory is a situation that is quite unfavorable for polygraph testing in terms of all of the factors just discussed. Other potential applications should be evaluated after taking these factors into account.
Polygraph testing is likely to look more attractive for some of these applications, even though in all applications it can be expected to yield a sizable proportion of errors along with the correct classifications. In this connection, it is worth revisiting the class of situations we describe as focused screening situations.
Events occurring since the terrorist attacks of September 11, , suggest that such situations may get increased attention in the future. Focused screening situations differ both from event-specific investigations and from the kinds of screening used with employees in national security organizations. An illustrative example is posed by the need to screen of hundreds of detainees captured in Afghanistan in late to identify those, perhaps a sizable proportion, who were in fact part of the Al Qaeda terrorist network.
Such a focused screening situation is like typical security screening in that there is no specific event being investigated, but it is different in that it may be possible to ask specific relevant questions, including questions of the concealed information variety. For example, members of Al Qaeda might be identifiable by the fact that they have information about the locations and physical features of Al Qaeda training camps that is known to interrogators but not to very many other people.
Another example might be the screening of individuals who had access to anthrax in U. Again, even though the examiners do not know the specific target action, they can ask some focused relevant questions.
The tradeoffs in focused screening are often very different from those in other screening situations because the base rate of the target activities may lie below the 10 percent or higher typical of criminal investigations. Tradeoffs may also be different in terms of the relative costs of false positive and false negative test results and in terms of incentives to use countermeasures.
A polygraph or other screening procedure that is inappropriate or inadvisable for employee security screening may be more attractive in some focused screening situations. As with other applications, the tradeoffs should be assessed and the judgment made on how and whether to use polygraph screening on the basis of the specifics of the particular situation.
We believe that it will be helpful in most situations to think about the tradeoffs in terms of which sensitivities might be used for the screening test, which false positive index values can be expected with those sensitivities, and whether these possibilities include acceptable outcomes for the purpose at hand.
One way to make the tradeoffs associated with polygraph screening more attractive would be to develop more accurate screening protocols for the use of the polygraph.
This section discusses the two basic strategies for doing this: improving polygraph scoring and interpretation and combining polygraph results with other information.
The 11 federal agencies that use polygraph testing for employee screening purposes differ in the test formats they use, the transgressions they ask about in the polygraph examination, the ways they combine information from the polygraph examination with other security-relevant information on an examinee, and the decision rules they use to take personnel actions on the basis of the screening information available.
Despite these differences, many of the agencies have put in place quality control programs, following guidance from the U. Department of Defense Polygraph Institute DoDPI , that are designed to ensure that all polygraph exams given in a particular agency follow approved testing procedures and practices, as do the reading and interpretation of polygraph charts. Federal agencies have established procedures aimed at standardizing polygraph test administration and achieving a high level of reliability in the scoring of charts.
The quality control procedures that we have ob-. We emphasize two things about reliable test administration and interpretation. First, reliable test administration and interpretation are both desirable in a testing program and essential if the program is to have scientific standing. Second, however, it is critical to remember that reliability, no matter how well ensured, does not confer validity on a polygraph screening program.
Attempts to increase reliability can in some cases reduce validity. For example, having N examiners judge a chart independently, and averaging their judgments, can produce a net validity that increases when N increases, because the idiosyncratic judgments of different examiners tend to disappear in the process of averaging.
Having independent judgments produces what appear to be unreliable results, i. If examiners see the results of previous examiners before rendering a judgment, apparent reliability would increase because the judgments would probably not differ much among examiners, but such a procedure would likely reduce the accuracy of the eventual decision.
Even worse, suppose instructions given to the examiners regarding scoring are made increasingly precise, in an effort to increase reliability, but the best way to score is not known, so that these instructions cause a systematic mis-scoring. The result would increase reliability, but would also produce a systematic error that would decrease accuracy. A group of examiners not so instructed might use a variety of idiosyncratic scoring methods: each would be in error, but the errors might be in random directions, so that averaging the results across the examiners would approach the true reading.
Here again there is a tradeoff between reliability and validity. These are just illustrations. We can envision examples in which increases in reliability would also increase accuracy.
The important point is that one should not conclude that a test is more valid simply because it incorporates quality control procedures that increase reliability. In addition to establishing examiner training and quality control practices at DoDPI and other agencies, the federal government has sponsored. This approach holds promise for making the most of the data collected by the polygraph. Human decision makers do not always focus on the most relevant evidence and do not always combine different sources of information in the most effective fashion.
In other domains, such as medical decision making Weinstein and Fineberg, computerized decision aids have been shown to produce considerable increases in accuracy. To the extent that polygraph charts contain information correlated with deception or truth-telling, computerized analysis has the potential for increasing accuracy beyond the level available with hand scoring.
The investigators from JHU-APL, in their publications and in oral presentations to the committee, have made claims about their methodology and its successful testing on criminal case data through cross-validation. We made extensive efforts to be briefed on the technical details of the JHU-APL methodology, but although we were supplied with the executable program for the algorithms, the documentation provided to us offered insufficient details to allow for replication and verification of the claims made about their construction and performance.
JHU-APL was unresponsive to repeated requests for detail on these matters, as well as on its process for building and validating its models.
On multiple occasions we were told either that the material was proprietary or that reports and testing were not complete and thus could not be shared. From the information available, we find that efforts to use technological advances in computerized recording to develop computer-based algorithms that can improve the interpretations of trained numerical evaluators have failed to build a strong theoretical rationale for their choice of measures. They have also failed to date to provide solid evidence of the performance of their algorithms on independent data with properly determined truth for a relevant population of interest.
As a result, we believe that their claimed performance is highly likely to degrade markedly when applied to a new research population and is even vulnerable to the prospect of substantial disconfirmation. In conclusion, computerized scor-. We end with a cautionary note. A polygraph examination is a process involving the examiner in a complex interaction with the instrument and the examinee.
Computerized scoring algorithms to date have not addressed this aspect of polygraph testing. For example, they have treated variations in comparison questions across tests as unimportant and have not coded for the content of these questions or analyzed their possible effect on the physiological responses being measured. Also, examiners may well be picking up a variety of cues during the testing situation other than those contained in the tracings even without awareness and letting those cues affect the judgments about the tracings.
Little evidence is available from the research literature on polygraph testing concerning this possibility, but until definitive evidence is available, it might be wise to include both computerized scoring and independent hand scoring as inputs to a decision process.
In most screening applications, information from polygraph examinations chart and interview information is not by itself determinative of personnel actions. Thus, polygraph information is often combined in some way with other information. We have been unable to determine whether DOE or any other federal agency has a standard protocol for combining such information or even any encoded standard practice, analogous to the ways the results of different diagnostic tests are combined in medicine to arrive at a diagnosis.
We made repeated requests for the DOE adjudication manual, which is supposed to encode the procedures for considering polygraph results and other information in making personnel decisions.
We were initially told that the manual existed as a privileged document for official use only; after further requests, we were told that the manual is still in preparation. Thus it appears that various information sources are combined an in informal way on the basis of the judgment of adjudicators and other personnel.
Quality control for this phase of decision making appears to take the form of review by supervisors and of policies allowing employees to contest unfavorable personnel decisions. There are no written standards for how polygraph information should be used in personnel decisions at DOE, or, as far as we were able to determine, at any other agency.
We believe that any agency that uses polygraphs as part of a screening process should, in light of the inherent fallibility of the polygraph instrument, use the polygraph results only in conjunction with other information, and only as a trigger for further testing and investigation.
Policy decisions about using the polygraph must consider not only its accuracy and the tradeoffs it presents involving true positives and false positives and negatives, but also whether including the polygraph with the sources of information otherwise available improves the accuracy of detection and makes the tradeoffs more attractive.
This is the issue of incremental validity discussed in Chapter 2. It makes sense to use the polygraph in security screening if it adds information relevant to detecting security risks that is not otherwise available and with acceptable tradeoffs.
Federal agencies use or could use a variety of information sources in conjunction with polygraph tests for making personnel security decisions: background investigations, ongoing security checks by various investigative techniques, interviews, psychological tests, and so forth see Chapter 6. We have not located any scientific studies that attempt directly to measure the incremental validity of the polygraph when added to any of these information sources. That is, the existing scientific research does not compare the accuracy of prediction of criminal behavior or any other behavioral criterion of interest from other indicators with accuracy when the polygraph is added to those indicators.
Security officials in several federal agencies have told us that the polygraph is far more useful to them than background checks or other investigative techniques in revealing activities that lead to the disqualification of applicants from employment or employees from access to classified information. It is impossible to determine whether the incremental. There are several scientifically defensible approaches to combining different sources of information that could be used as part of polygraph policies.
The problem has been given attention in the extensive literature on decision making for medical diagnosis, classification, and treatment, a field that faces the problem of combining information from clinical observations, interviews, and a variety of medical tests see the more detailed discussion in Appendix K.
Statistical methods for combining data of different types e. In one, called independent parallel testing, a set of tests is used and a target result on any one is used to make a determination.
For example, a positive result on any test may be taken to indicate the presence of a condition of interest. In the other approach, called independent serial testing, if a particular test in the sequence is negative, the individual is concluded to be free of the condition of interest, but if the test is positive, another test is ordered. Validating a combined test of either type requires independent tests or sources of information and a test evaluation sample that is representative of the target population.
Serial screening and its logic are familiar from many medical settings. A low-cost test of moderate accuracy is usually used as an initial screen, with the threshold usually set to include a high proportion of the true positive cases people with the condition among those who test positive.
Most of those who test positive will be false positives, especially if the condition has a low base rate. Their admission depends on where the case is brought which state, or which federal district, if it's a federal case. The states and the federal courts use different legal tests to determine whether polygraph results are admissible. But, the important point to remember about lie detector tests is that they are processes designed to gather evidence against you.
Whether that evidence comes from the pre-test questions, the post-test interview, or the test results themselves, all of it is designed to gather enough evidence so the state can pursue its investigation, charge the case, and convict you of a crime.
Even if a court refuses to allow the results of the test as evidence in a trial, the prosecutor can use the results and statements you make in the pre or post-test interview to assist him in developing the case against you. Some employers give employees lie detector tests if, for example, those employees have access to sensitive or classified information. Other employers might ask employees to submit to a lie detector test if someone has stolen money from the company, or as a condition of employment during the hiring process.
In general, employers cannot use polygraph tests to screen potential employees or to fish for information from current employees, but they can use the tests if they have a good, work-related reason and the tests are narrowly focused. There is no clear answer when it comes to deciding whether to take a polygraph test, whether you've been asked by the prosecutor or would like to take a test to establish your innocence. Either way, it's vital you speak to an experienced criminal defense attorney as soon as possible.
If, after consulting with your attorney, you decide that you want to take a polygraph, it's always better to hire your own test administrator instead. You need to speak to a criminal defense attorney as soon as you are questioned by criminal investigators, even if you don't believe you have done anything wrong.
The information provided on this site is not legal advice, does not constitute a lawyer referral service, and no attorney-client or confidential relationship is or will be formed by use of the site. The attorney listings on this site are paid attorney advertising. Offenders are prohibited from refusing to take a polygraph test on pain of a prison sentence of up to 5 years.
Lie detector or polygraph tests are not being used to detect or solve crimes. This might seem odd, but the lie detector is used to help the police or probation service manage the risk that a suspect or offender might pose whilst in the community.
For example, they want to know the truth about whether someone is really having contact with children behind their backs, or is thinking about child abuse. Many sex offenders have special orders restricting movement or use of the internet, and the police want to know if they are sticking to them. This information is known as a Risk Relevant Disclosure and the police can then take whatever action is appropriate. They are trying to keep the public safe. Equally, police are not particularly relying on the results of the lie detector.
Rather, they mostly rely on what the subject tells them before or after the test. However, all of the research shows that the number of Risk Relevant Disclosures massively increases when lie detectors will be or have been used. In the face of the test, many confess, and this is the key to its usefulness. Polygraph testing may be controversial in some quarters but it is not some bogus science.
There are strict and complex codes of practice and an examiner must undergo extensive training. Such are the demands of the job that research recommends that examiners do the job exclusively. Most best practice has been imported from America, where polygraph testing is much more established and regulated. It only ever forms one part of a range of available management tools.
If the latter are, they're guilty. The more practiced you are at lying, the less anxiety is associated with it. A polygraph test can sometimes be correct, and sometimes be wrong. Controlled lab studies have found that the tests are generally capable of correctly identifying a liar at rates greater than chance, but also incorrectly indicate that lots of honest people are lying too.
And the National Research Council has concluded that even these trials are flawed, because they depend on people's responses to mock crimes, which probably don't reflect real-world emotions. When accused of an actual crime, many people understandably become anxious, even if they're innocent.
Even worse, these trials aren't conducted on people trained in what investigators call "countermeasures": various strategies aimed at beating the test. Experts conclude that polygraph tests probably are beatable by people with training, a belief demonstrated by the federal government's recent attempts at arresting people offering to teach these methods.
Because of all this, the American Psychological Association has recommended against using polygraph tests in investigations or employee screening. Research has consistently shown that polygraphs are not an effective way to reduce recidivism among sex offenders. And t he National Research Council has gone so far as to say that federal agencies' overconfidence in the test for screening " presents a danger to national security objectives. Despite the legal ban on private employers using polygraph tests and the court decision ruling that their results are inadmissible as evidence in federal courts, there are huge loopholes in place — and they're exploited by federal employers, law enforcement, probation officers, and others.
But if there's so much evidence that polygraphs don't detect lies, why are these people bent on using them? It doesn't matter whether the test actually works, just that it's perceived as effective. One possibility is the belief that they're useful as a prop — part of what Saxe calls the "theater" of interrogation.
Related is the belief that polygraphs might be useful as a deterrent: If a sex offender believes he or she is going to be regularly subjected to accurate lie detection tests, committing a crime suddenly looks like a guarantee of heading back to prison.
For both of these uses, it doesn't matter whether the test actually works, just that it's perceived as effective. But Saxe believes that for some people, there may be a less cynical factor involved — something that more closely resembles myth or religion than science.
0コメント