Disability Prevalence -- Where Are We?

This post summarizes the general flow of my posts on disabilities over the past half-year.  I still have a few more posts in draft form, and I'll be wrapping those up shortly, but this is a good point at which to sketch out the picture as it has developed in this blog.

This post originated as an e-mail message to a researcher who seemed potentially interested in looking into data on disabilities.  I wanted to summarize, for him, the questions I have been studying.  As the message grew longer and began to cite my other blog posts, I realized that I should probably just put it up on the blog and refer him to it.  So what was going to be an e-mail message has now become the following paragraphs.

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Let me describe the situation in general terms, and see if there are particular aspects of it that seem to have the best potential for further investigation from a research perspective.  I tend to be somewhat philosophically oriented, so my apologies in advance if it takes me a while to reach the ground.

What the Question Is

The general question is, how many people have disabilities?  There is a definitional aspect to that question.  Speaking strictly from my own perspective, I have posted some blog entries about such matters.  This definitional question matters in the sense that, if we make the circle too small, we deny relevant assistance to people who need it.  An example, in the area of mental disability, is a person who does not qualify for an official psychiatric diagnosis but nonetheless experiences obvious difficulty.

That general question is operationalized in various surveys.  At this level, we move from the purely conceptual to a mix of the hypothetical and the actual.  Elsewhere, I have cited references to a so-called National Disability Data System (NDDS).  The NDDS itself does not exist formally; the concept is that it exists in effect, through the data provided by actual research efforts.   This is still an academic's discussion; at this level we are kicking around various ways of going at the question of disability prevalence.

From there, we move to a more concrete level.  This is the level at which politicians and the public are given specific numbers.  They may not be the right numbers, but that's what footnotes are for.  Most notably, the American Community Survey (ACS) replaces the decennial census; that is, questions about disabilities have disappeared from the latter because the prevalence of disabilities is now being estimated rather than counted.  The ACS is in the process of replacing the census, for this purpose, down to the local level.

Why It Matters

As you can see, I have been trying to get a grasp on what we think we know, and why we think we know it.  But why does it matter?  Why should we care about the prevalence of disabilities?  There seem to be two ways to answer that.

The National Perspective

On one hand, we can approach the issue from a national perspective.  As the posts describe, the disability-related questions on the ACS have been modified, in the last few years, for purposes of improved reliability.  All well and good; but in the process, the estimate of people with disabilities dropped by some 15%.  Meanwhile, more sensitive measures (e.g., the SIPP) have the potential (but, alas, not the financial backing) to show a significantly higher rate.

The nation has a profound interest, budgetary and otherwise, in knowing whether the number of people with disabilities is 38 million or, instead, 53 million (to cite one alternate figure that I have encountered).  A million people here, a million people there, and pretty soon we're talking about real people.  The estimates are definitionally driven, of course, but that's the point:  how much higher does the prevalence rate go if the researcher uses a different, but comparably respectable, definition?

For example:  in an interesting book, Bagenstos contends that the Americans with Disabilities Act (ADA) has been developed in the direction of treating disability as a minority-rights kind of issue.  This, he says, has had the advantage of drawing upon the legacy of civil rights movements of the 1960s and 1970s, thus giving disability rights advocates a certain automatic sense of legitimacy.  The drawback has been that such movements invite opposition from those whom they exclude, particularly if the latter are expected to pay for adjustments to rectify perceived wrongs.

The alternative, Bagenstos says, is to treat the condition in question -- disability, in this case -- as a universal issue, something in which everyone partakes, or is at risk of partaking, through various forms of inability and imperfection.  In this approach, disability prevalence can be calculated without segregating "people with disabilities" into their own conceptual ghetto.  If disability is treated as something that anyone is capable of experiencing, like chickenpox or the flu, but if only a fraction of the population is likely to experience it at any particular point, what is that fraction?

Good question.  But how can we answer it?  The budgetary infeasibility of extending the SIPP to localities across the entire nation, on a par with the ACS, demonstrates that national disability prevalence estimation is presently stuck in a rather absurd place.  Because of its lack of local foundation, it can be gerrymandered, from a desk in D.C., to add or drop five or ten million people here and there, for reasons of statistical or budgetary convenience.  The nation, and the disability community, need something better than that.  The following suggestion illustrates a national alternative on the local level.

The Local Perspective

The relatively narrow operationalization of disability in the ACS is obviously problematic.  If its national estimate of disabilities is on the conservative side, its local estimate will tend to be so as well.

That seems reasonable enough.  But putting it that way highlights a bigger problem.  The idea seems to be that the best way to know whether my neighbor has a disability is to wait for the latest ACS to be completed; wait for the local-level ACS data to be compiled by someone in Washington; adjust that local number upwards by a fudge factor due to the conservative bias of the ACS; and then calculate my neighbor's odds.

Faced with that kind of logic, practical decisionmakers and advocates say, in effect, "Research be damned."  They aren't going to plumb the intricacies of the Supreme Court's latest interpretations of the Americans with Disabilities Act, and they aren't going to invest the time required for a clear understanding of the ACS.  They're going to rely, instead, on what they've heard and what they believe, supplemented by the occasional citation to some source or other.

Suppose we began, instead, from present experience.  Suppose, for example, that I cannot walk to work.  Research on the benefits of outdoor exposure suggests that this state of affairs will tend to make me less happy than I would be if I could walk to work.  The reason for this impairment of my subjective well-being may not be crucial:  it may not matter, for that purpose, whether I can't walk to work because I have no legs or, instead, because the streets between here and there are dangerous for pedestrians.  Either way, I can't do it.

The focus, in that example, is upon achieving a certain outcome.  Outcome-oriented disability estimation is, in essence, the language of actual local life.  The mayor finds that 39% of her constituents are furious about the state of the roads.  They are experiencing some transportation-related disability.  The fact that 3% of constituents are furious about the state of the sidewalks may be politically trivial, but a transportation-related disability nonetheless exists there as well.

Improved accessibility will often be politically infeasible if the public impression is that we are trying to spend a fortune on curb cuts for a small number of people in wheelchairs who never use the sidewalks anyway.  Rather than ask for special handouts, a more defensible view of transportation-related disability would focus on getting the roads and sidewalks into shape for people on foot, in wheelchairs, and in cars.  Infrastructure is essential.  Everyone needs effective transportation.

Summary

Disability has been defined in different ways.  A cursory review suggests that American law is presently oriented toward treating a disability as a flaw in the individual.  Hence, instruments like the ACS look for vision impairments and other personal characteristics that prevent people from functioning like everybody else.  The social model of disability is incorporated only in the limited sense that some survey questions acknowledge, in various ways, that disability may entail mismatch between person and society; yet even that acknowledgement inevitably brings the focus back to the individual.

That approach to disability has the potential to get everyone bogged down in mutual recrimination, with the familiar old vocabularies of "handouts" versus "privilege," and "normal people" versus "the oppressed."  An approach that could be more readily calculated on the local level, and more consistent and politically supportable on the national level, would focus upon desired life outcomes.

Using transportation as a particularly important disability-related outcome, one can ask how many people are not able to get where they need to go within a reasonable amount of time, in a reasonable manner, at reasonable cost.  There are many kinds of transportation-related disabilities in this sense.  Here are some examples:

• People who are disabled from independent transportation because they are under the control of others.  Examples include children and prison inmates.  
• Those whose health precludes independent travel -- hospital inpatients, for instance, and nursing home residents.
• People may also be economically disabled from utilizing independent transportation:  for instance, they may not have money for a car or even for bus fare, assuming there is a bus line near them.
• People whose obligations prevent independent travel:  people have to stay at work, or have to stay near a certain location to be available for work, or have to stay home with the kids or with a sick relative.
• Social disability precluding independent transportation.  People are stared at and harassed if they are someplace where, in effect, they don't belong.  This can include kids in the vicinity of a bully, women who are out late alone, bicyclists on a busy street, individuals of an unfamiliar or unwelcome race, and people who dress funny or act funny.

The purpose of such an investigation would be to provide an alternative perspective that would be more immediately familiar to the public and more responsive to actual human experiences of disability.  The idea is that, for whatever reason, some people can't get where they need to go.

Needless to say, this post does not purport to address the gamut of disability-related concerns and issues.  Indeed, it is precisely not that sort of thing.  What I have observed, in my half-year of exposure to disability-related matters, is that the cerebral model of disability -- the one that begins with abstract, individual-oriented definitions and works its way down to concrete application -- is not really very practical.

It tentatively seems that it would be more useful, marketable, and appropriate to treat disability as a matter of sociopersonal constraints that everyone experiences in various forms, and to focus especially upon those global, national, state, and/or local conditions that most profoundly impair the achievement of the most important outcomes.  This approach would still prioritize many individual impairments, but would do so as a matter of an investment in society's future rather than as a handout to a person who has managed to become privileged in the eyes of the law.

American Community Survey: 2008 Update: Defining Disability

In previous posts, I have looked into the prevalence of disabilities in the United States, as measured especially by the American Community Survey (ACS), especially in 2003. This post takes a first step toward updating the ACS measurement of disabilities, in light of changes made between 2003 and 2008.  The focus here is on the definition of disability under the 2008 ACS.

As of 2008, the ACS 2008 Subject Definitions (p. 38) defined disability as “the restriction in participation that results from a lack of fit between the individual’s functional limitations and the characteristics of the physical and social environment.” The Census Bureau asserts that “disability is not seen as intrinsic to the individual”; nonetheless, the Bureau also identifies “four basic areas of functioning” in which respondents might have “serious difficulty.” In that sense, the language still seems to reflect an impression that disabilities are the individual’s problem, rather than a mutual “lack of fit.” For instance, one might expect a different outcome if respondents were presented with a broader inquiry into functional limitations perceived either by themselves or by others in their lives (e.g., employers, neighbors, family members).

In what the Subject Definitions (p. 38) describe as “a conceptual and empirical break from earlier years,” the 2008 ACS still had six questions about disabilities, but now sought to identify “serious difficulty in four basic areas of functioning: vision, hearing, ambulation, and cognition,” and also included “two questions to identify people with difficulties that might impact their ability to live independently.”

These changes followed from a 2006 American Community Survey Content Test, whose results in the area of disability were written up by Brault and Stern (2007) in an Evaluation Report Covering Disability. The 2006 Content Test was driven by a concern with improved reliability in survey results (Brault & Stern, p. 9), not by a concern with capturing the full numbers of people with disabilities. To the contrary, Brault & Stern admit that some of the changes in the ACS disability questions tend to reduce reported prevalence (p. 8) and that the 2006 Content Test used data collection modes that contained “inherent barriers to collecting disability data” (p. 15). The latter point is important because the regular ACS appears to use essentially the same methods.

In a separate report attached as Appendix B to the Brault and Stern (2007) report (above) (i.e., beginning at page 33 of that PDF), Miller and DeMaio (2006) indicated that, for purposes of consistency with the Americans with Disabilities Act (ADA), an unspecified ACS subcommittee determined that disability would be defined as “a mental or physical impairment that substantially limits at least one major life activity” (p. B-2).  That subcommittee appears to have approached that question by exploring “domains of limitation” or “limitation domains” (pp. B-2, B-3), instead of taking the seemingly obvious step of deciding what counts as a major life activity.

To cite some rather choice examples, Miller and DeMaio did not indicate that the subcommittee considered sleep, sex, or socializing to be major life activities.  All three of those examples seem to involve the Census Bureau’s alleged orientation toward the two-sided question of fit between person and society.  It is society that supplies the people, the stresses, and other key components and determinants of sleep, sex, and socializing.  One would expect, in other words, that these three would be prime candidates for inclusion in the list of major life activities, or as essential contributors thereto.  For instance, there is evidence that sleep deprivation significantly interferes with work and other major daily activities of tens of millions of Americans (Baxter & Kroll-Smith, 2005, p. 39), that it results in substantial numbers of injuries and deaths (e.g., Lyznicki, Doege, Davis, & Williams, 1998), and that one-third of Americans take naps on a typical day (Taylor, 2009).  Although it is presumably not necessary to do so here, one certainly could develop a more extensive argument for sleep, and could make similar arguments for the inclusion of sex, socializing, and other activities that the subcommittee somehow considered not to be "major" for purposes of detecting the existence of a disability.

The subcommittee's decisions in this regard might have been more defensible if the ADA had been construed as taking an interest in major productive activities.  Viewed that way, the subcommittee could reasonably conclude (especially in a traditional industrial economy) that it is all right if workers are tired, as long as they keep working.  Likewise, if industrial-type productivity were the stated focus, attention to sex and socializing would probably seem humorously superfluous.  The full list of impairments that mattered to the subcommittee -- involving vision, hearing, lower body mobility, cognition, activities of daily living (ADLs), instrumental activities of daily living (IADLs), and work (Miller & DeMaio, 2006, p. B-3) would then make sense.  ADLs “generally include self-care type activities such as bathing and dressing,” and IADLs are activities often associated with independent living such as going out alone to shop or visit a doctor’s office” (Brault & Stern, 2007, p. 4), all of which align with an emphasis upon the worker's functionality and his/her ability to remain functional.

Ironically, contrary to the apparent purpose of the ADA, a functional orientation can reinforce stereotyping and exclusionism.  If the majority defines functionality in terms of what the majority can do, then those in the minority will tend to occupy an inferior role.  It will be newsworthy when technology enables them to overcome – say, to run faster than those who began with what was, by definition, a functional advantage (e.g., Christie, 2009).  In reality, there may be many ways (involving e.g., sleep, sex, or socializing) in which many putatively high-functioning people are experiencing profound limitations in major life activities; but that will not be recognized in the ACS until a standard other than industrial-type functionality is used to guide disability determinations.  There would seem to be a number of good, currently relevant candidates for such a standard – ranging from “life, liberty, and the pursuit of happiness” to social capital to adjustment to or satisfaction with life – that could be used alone or in combination for that purpose.

The apparent functional orientation was not the only way in which the 2008 ACS reduced the count of disabilities even below what one might have expected from the subcommittee’s own stated concept. The survey discarded the subcommittee’s broad interest in mental and physical impairments, in favor of very limited kinds of difficulties. The survey’s only questions about mental disabilities were as follows:

18a. Because of a physical, mental, or emotional condition, does this person have serious difficulty concentrating, remembering, or making decisions?

19. Because of a physical, mental, or emotional condition, does this person have difficulty doing errands alone such as visiting a doctor’s office or shopping?

Bizarrely, the 2008 ACS no longer has even the question about work disability (Brault & Stern, 2007, p. 7). That is, there is no question about the presence of a physical, mental, or emotional condition that would limit the kind or amount of work a person can do. So if someone has no problem concentrating etc. (Question 18a), and does not have difficulty doing errands alone (Question 19), it seems s/he would not have a work disability even if s/he spent the workday standing on his/her desk and screaming.

Apparently the question about work disability was deleted because Miller and DeMaio (2006, p. B-32) claimed there was an “excessive extent of misinterpretation and misreporting in this question.” One objection Miller and DeMaio cited had to do with vagueness in the word “work.” Some people reportedly took it to include work around the house. That raised interesting questions in itself, but in any event one version of the test question specified work “at a job or business” (p. B-31). Despite the alleged breadth and complexity of the work construct, Miller and DeMaio devoted only about 1.5 pages to the question of work before recommending its deletion.  (While I did not think that disabilities should be defined exclusively in work-related terms, it did seem obvious that inability to work would be an important indicator of disability.)  That is, Miller and DeMaio did not seriously wrestle with the matter; yet they also did not claim that the question of work-related disability is unimportant.

Bear in mind that Miller and DeMaio (2006), who balked at what they consider excessive vagueness in the work construct, were the same researchers who pointed out that “Respondents’ answers to survey questions are necessarily based on personal experience and perceptions of that experience” (p. B-3), that “it is unfeasible to develop questions that yield a perfect measure of disability” (p. B-4), and that, in connection with a question that was retained in the survey, respondents were being required “to discern a clear line of yes or no in a reality that, for them, was essentially grey and multi-dimensional” (p. B-7). All of these remarks seem to suggest that Miller and DeMaio were generally comfortable with the hard decisions that arise in the process of quantifying experience – including work experience.

Under such circumstances, one might be forgiven for asking whether political considerations during the Bush Administration had any influence upon the choice of researchers and/or the recommendations they made in such regards. In a report on changes to measurement of disability in the 2008 American Community Survey that was produced after Obama’s election, Brault (2009, p. 5) seems to indicate that the previous administration had not prioritized the ACS generally. He says that, “due to budgetary issues, FEFU [i.e., Failed Edit Follow-Up] operations were scaled back from April through September” of 2008.

In his 2009 report, Brault states that the net effect of the changes in questions on the 2008 ACS, including the deletion of the work disability question, resulted in a marked drop in the estimated number of Americans with a disability, from 41.2 million (2007) to 35.9 million (2008). “Given the differences in the questionnaire,” Brault says, “one should not interpret these changes as real differences in the number or percent of people with disabilities” (p. 16).  Brault emphasizes that ACS disability data from 2008 are not comparable with ACS disability data from prior years.

This is not to say that the 2008 ACS is useless for all disability-related purposes. Brault (2008, p. 8) suggests, for example, that the ACS is more likely to capture instances of hearing difficulty than is the Survey for Income and Program Participation (SIPP), because the SIPP excludes hearing difficulties that are corrected by hearing aids. That particular example is not necessarily good or bad in itself, but it does suggest that the ACS may sometimes provide a useful alternate picture on the prevalence of some kinds of disabilities.

There are some other limitations on ACS data.  First, ACS data of all sorts are not yet available for geographic areas with populations of less than 20,000.  In late 2010, according to the Census Bureau, data will be released “for areas as small as census tracts and block groups, nationwide. For very small towns, 2010 will be the first time that ACS data are published. These data products, referred to as 5-year multiyear estimates, will be based on the data accumulated during the 2005-2009 time period.”  The Bureau also says that information on demographic, socioeconomic and housing characteristics will thereafter be available annually for all areas.  These include annual estimates for all areas of 65,000+ population, three-year averages for all areas of 20,000+ population, and five-year averages for census tracts and block groups.  Note also that, starting in 2006, the ACS did begin to include data for the group quarters population.  These data were not available, however, in 15 states that had a total group quarters population of less than 45,000.

Because of the change in the operational definition of disability in the 2008 ACS, the Census Bureau will not be able to provide three-year estimates for disabilities until the 2008-2010 ACS 3-year estimates are released in 2011.  That is, the change in definitions means that users should not compare disability data from 2008 and afterwards to any year before 2008.

Recap So Far

In this series of posts on the prevalence of disabilities in the U.S., I have been moving toward an estimate of disabilities on the local level.  It seemed logical to begin by choosing a national-level survey that would provide local-level data, and then to understand that survey and, on that basis, to interpret its local data.  Preliminarily, the ACS seemed far superior to other federal surveys, in terms of its penetration to the local level.  It did not define disabilities as comprehensively as some other surveys, but it seemed that it might be possible to adjust its reported prevalence rates upwards by some plausible percentage, so as to reach a defensible ballpark figure for actual local disability prevalence.

Unfortunately, this post's critique of the definition of disabilities, and of its operationalization in the 2008 ACS, suggests that the ACS does not provide accurate data on the prevalence of disabilities.  Hence, before conducting further research into federal disability statistics, it presently seems advisable to pursue some other routes.  Several such routes come to mind.  First, there is surely a great deal of relevant third-party literature on the ACS, as distinct from the literature provided by the Census Bureau itself.  Second, there may be good local-level research on the prevalence of disabilities in various types of cities and counties, sufficient to inform an educated guess on prevalence in other similar local areas.  Third, on a more theoretical level, there is no doubt much to learn about the conceptualization of disability -- on, for example, the validity of viewpoints suggested in this post.  Since the conceptualization seemed likely to influence the interpretation of research, my next step in this investigation moved in the conceptual direction.