How Chiropractors Think and Practice:
The Survey of North American Chiropractors

This section is compiled by Frank M. Painter, D.C.
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FROM:   Soc Sci Med. 2011 (Jun); 72 (11): 1826–1837 ~ FULL TEXT

William P. McDonald, MS Ed, DC, Keith F. Durkin, MS, PhD, and Mark Pfefer, MS, DC

Cleveland Chiropractic College,
Kansas City, MO.

For the past 100 years, chiropractic leaders in North America vigorously debated (1) whether the profession’s scope of practice should be restricted to the examination and adjustment of the spine or expanded to include a broad range of procedures from physical and general medicine and (2) whether the spinal adjustment is or is not an effective treatment for many early-stage visceral conditions. While leaders debated, the opinions of practicing chiropractors were never systematically surveyed. This probability survey seeks to ascertain the opinions of practicing chiropractors on the issues and questions that arise from the historic conflict between broad scope advocates and focused scope proponents. This is a systematic random attitudinal survey of 1,102 practicing chiropractors selected from a mailing list of 60,409 names from Canada, Mexico, and the United States. The 687 respondents (63.3% response rate) produced four major findings: (1) numerous survey items repeatedly show that >75% of the survey subjects favor a broad scope of clinical services, (2) several items show that >75% of the respondents empirically find that the adjustment of the vertebral subluxation complex usually elicits improvements in select visceral ailments, (3) majorities of self-labeled broad scope, middle scope, and focused scope chiropractors agree on all but one issue, and that is (4) respondents divide rather evenly on the question of limited prescription rights for the profession. Practicing chiropractors in this survey form a consensus on many scope of practice and philosophical issues, in contrast to the history of conflict among leaders in the profession.

Key Indexing Terms   chiropractic, chiropractors, survey, scope of practice

From the FULL TEXT Article:


For much of the past century, a variety of educators and leaders in the chiropractic profession engaged in a robust and, sometimes, fractious debate on clinical and philosophical issues. This ongoing debate—coupled with little or no survey feedback from practicing chiropractors—forges the prevailing hypothesis: chiropractors are divided on the salient questions, are clustered into rival camps, and practice in divergent ways. Much of the profession’s tug-of-war is documented in Peterson and Wiese’s history text.1

The purpose of this survey is to ascertain the attitudes of North American chiropractors on the more contentious aspects of scope of practice and philosophy. The primary goal is to ascertain the degree to which the profession is, or is not, united.

Despite sporadic public discord among the profession’s institutional leaders, the working hypothesis for this survey is that most practicing chiropractors display considerable unity in the way they think on the issues and practice in the clinic. The assumption is that, while there are those who disagree on various aspects of chiropractic, a consensus exists on most of the key issues.

This is the first probability survey of North American chiropractors. Previous surveys of this type in North America were restricted to chiropractors in specific organizations and jurisdictions or were hampered by low response rates. Other large attitudinal surveys were of the nonprobability variety.

Literature Review

A survey of Canadian chiropractors finds 19% rejecting traditional chiropractic philosophy, 22% endorsing traditional chiropractic tenets, and 59% taking a moderate stand.2 It should be noted that this survey suffers from unfortunate wording in some of the belief statements to which the respondents are asked to agree or disagree (5-point scale). The most egregious wording is found in this belief statement: “The scope of chiropractic practice should be limited to musculoskeletal conditions” (italics added).2 Practice is the wrong word.

This specific debate among chiropractors has focused on whether the vertebral adjustment should be limited to musculoskeletal conditions. After all, chiropractors from all points on the continuum have historically treated visceral conditions. For example, broad scope (“mixer”) chiropractors have used vitamins, herbs, homeopathic medicines, biofeedback, exercises, etc., in an attempt to restore health in visceral ailments. Likewise, focused scope (“straight”) chiropractors have adjusted the vertebral subluxation in an attempt to normalize nerve activity to ailing visceral tissues. In short, the essence of this issue is about whether adjusting the subluxation actually contributes to healing and the correction of visceral dysfunction.

In a cross-sectional, practice-based study of 161 chiropractors who treat an above average percentage of visceral conditions, Hawk et al.3 found that 10.3% of the chief complaints involve nonmusculoskeletal conditions. Thus, even among practitioners with an interest in treating nonmusculoskeletal conditions, the proportion of patients seeking such care is relatively low.

In a randomized sample of U.S. chiropractors (658 respondents, 44% response rate), Rupert4 found that periodic maintenance care is recommended to 79% of chiropractic patients and that 34% comply. The article noted that 90% of the chiropractors agreed or strongly agreed that optimizing health was one of the purposes of maintenance care.

In a deft think piece on the rationale for chiropractic as a profession, Hawk writes: “[The adjustment] must be informed by a unique approach to healing and health that is distinct from, although not necessarily at odds with, the medical model. For it is the philosophy, the intuitive knowledge— the belief system—that differentiates a complete system from a procedure.”5

Of 753 chiropractors randomly sampled (65% response rate) by Hawk and Dusio,6 90% see themselves as primary care practitioners, 78% recently made referrals to MDs and DOs, and 71% perform a complete health history on every patient.


This postal survey reflects the opinions of respondents from Mexico, all major regions of Canada, and all 50 states in the United States.

The Ohio Northern University Institute for Social Research provided advice and counsel prior to mailing the survey instrument and, later, performed the data analysis. A draft version of the survey was pretested on a nonrandom sample of 35 chiropractors. Revisions were then made to the survey.

The final sample was generated using Dynamic Chiropractic’s 60,409 names, including 56,026 U.S. chiropractors, 4,324 Canadian chiropractors, and 56 Mexican chiropractors. The names on each of the three national lists were in zip code/postal district order. The three national lists (strata) were then linked (not combined) to make one master list. After a random start, every 54th name was selected from this master list to produce a systematic random sample of 1,102 chiropractors. This sampling pool contained 1,024 U.S. chiropractors, 76 Canadian chiropractors, and 2 Mexican chiropractors. The systematic methodology (every 54th name), when combined with a random start and lists arranged by zip code, gives every name a known probability of selection while ensuring geographic diversity.7

Of the 1,102 surveys mailed, 16 were returned from the post office due to invalid addresses. From the 1,086 surveys with valid addresses, 687 surveys were mailed back by respondents. This translates into an overall response rate of 63.3%. This response rate compares favorably with large probability surveys of health care practitioners. Three examples: Job Analysis of Chiropractic8 produced a response rate of 43%; “Canadian Chiropractors’ Attitudes Towards Chiropractic Philosophy and Scope of Practice”2 produced a response rate of 68.3%; and “A National Survey of Primary Care Physicians”9 produced a response rate of 62.7%.

Thirty-two surveys were excluded from the final analysis for one of the following three reasons: (1) the respondents indicated they were no longer practicing chiropractors (n  7); (2) surveys were received after data analysis had commenced (n  4); and (3) the majority of a survey was incomplete (n  21). It is a common practice to exclude surveys that have large amounts of missing data or invalid responses from analysis.10-12

There are basically four types of errors that can flaw a probability survey: coverage error, sampling error, measurement error, and nonresponse error.13,14

Attempts were made to minimize coverage error by using the largest available mailing list (Dynamic Chiropractic’s 60,409 names) and using selection methodology to give each name a known probability of being included in the sample.

Sampling error was minimized by insuring that a large number of names were selected (1,102), which netted 687 respondents, of which 655 survey instruments were usable.

Measurement error, which results from such things as unclear questions and impossible answers, was addressed in several ways. The questions were critiqued by 11 individuals, primarily chiropractors and social scientists. The questions were field tested with 35 chiropractors who were asked to provide feedback about the questions after they completed the survey; changes were made in the survey based on the field testing. Once the official survey was conducted, 21 questionnaires were discounted because of failure to complete large amounts of the survey. The returned survey instruments were reviewed for answers that were impossible or did not follow instructions.

Nonresponse error appears when there is a marked difference in the type of people responding and not responding. A geopolitical breakdown of the respondents shows that all regions responded adequately:

(1)   Eastern United States produced 46.6% of the respondents (vs. 49.6% of the original sample),
(2)   Western United States yielded 45.2% of the respondents (vs. 43.6% of the sample),
(3)   Canada produced 8.0% of the respondents (vs. 6.5% of the sample, and
(4)   Mexico yielded 0.3% of the respondents (vs. 0.2% of the sample).

Surveys with a response rate below 60% are more prone to nonresponse error.7,15

For those variables that were measured on a scale, the mean is reported as the measure of the central tendency and the standard deviation is reported as a measure of variability. For those variables that were measured at the nominal level, the 95% confidence interval is also reported. This indicates that one can be 95% certain that the actual number lies within the reported range of values.16

For those relationships involving variables measured at the nominal level, the Chi-Square test for independence was used. A significant result for this test suggests that the frequency distribution for one variable is related to (or dependent on) the categories for the second variable and the two are thus correlated.17,18

For those relationships in which the dependent variable was measured on a scale, a statistical procedure called an Analysis of Variance (ANOVA) was used to compare the mean scores. A significant result for the ANOVA test indicates that the observed differences in the mean scores are unlikely due to chance.18 However, when the independent variable has three levels, it is necessary to use a second “post-hoc” test to determine which precise mean scores are significantly different. In those instances, the Fisher LSD (least significant difference) test was utilized. This is an appropriate test when, as is true in this study, there are only a few variables being compared.19


The survey subjects were divided rather evenly in terms of their years in practice: 34% (≤10 years), 35% (11-20 years), and 31% (≥21 years). The ages of respondents included 32% who were ≤39, 61% who were 40-59, and 8% who were ≥60. Males made up 66% of the subjects.

In their day-to-day practice, 23% reported using one of the traditional-force spinal adjusting techniques, 10% claimed one of the low-force methods, and 67% indicated they employ both approaches. Nearly 90% of the subjects owned their practice, while 10% did not. The respondents came from practices of varying sizes: 46% personally treat ≤99 patients weekly, 30% treat 100-149 patients per week, and 24% see ≥150 each week. Annual net income for the survey subjects also varied: 56% made ≤$99,999, 24% earned $100,000 to $149,999, while 20% netted ≥$150,000.

The level of prechiropractic education included 66% with a bachelor’s degree or higher, 17% with an associate’s degree, and 16% without a degree. Prior to attending chiropractic college, 22% of those surveyed had a relative or family member who was a practicing chiropractor. Before enrolling in chiropractic school, 76% had been under the care of a chiropractor at one time or another.

The survey subjects included alumni from 18 chiropractic colleges in North America, in additional to several other chiropractic schools. The eight largest alumni groups included graduates of Palmer (Davenport) 23%, Life (Marietta) 11%, National 10%, Logan 7%, New York 7%, Canadian 6%, Northwestern 5%, and Southern California 5%.

      Univariate Findings

Table 1

The philosophical distribution of the respondents is presented in Table 1. Using the three definitions below, they self-rated their personal clinical philosophical positions on a 9-point scale.

Broad Scope allows a wide array of manual and other clinical procedures for diagnosing and treating both symptoms and neuromusculoskeletal conditions. Some in this camp would include minor surgery, obstetrics, and prescribing medications.

Middle Scope tends to combine subluxation adjusting with other conservative treatment and diagnostic procedures.

Focused Scope emphasizes the detection and adjustment of vertebral subluxations to restore normal nerve activity to musculoskeletal and visceral tissues. Some in this camp oppose therapeutic modalities, extremity adjusting, and diagnostic procedures.

By collapsing the data in Table 1, we see that the respondents make up three broad philosophical groupings: middle scope (46.4%), broad scope (34.3%), and focused scope (19.3%).

In response to the question, “Should chiropractic retain the term vertebral subluxation complex?,” the respondents (n = 638) overwhelmingly voted to do so: 88.1% yes (95% confidence interval 85.5-90.7), 11.9% no (95% CI 9.3-14.5).

To the question, “Should the adjustment be limited to musculoskeletal conditions?,” 89.8% of the respondents (n = 646) answered no (95% CI 87.4-92.2) and 10.2% yes (95% CI 7.8-12.6).

Given the question, “In what percentage of visceral ailments is the vertebral subluxation a significant contributing factor?,” the respondents gave a mean response of 62.1%. In short, the respondents, as a group, are of the opinion that the subluxation contributes to about 6 of every 10 visceral ailments. The 26.0 standard deviation indicates a wide dispersal of responses, including these two statistically extreme attitudes: 10.9% believe the subluxation contributes to 100% of all visceral ailments, and 1.5% believe the subluxation never contributes to visceral ailments.

When asked, “Do adjustments usually elicit improvements in the following cases?,” a majority of the respondents answered in the affirmative for four select conditions:

(1)   migraines   (n = 633): yes 89.3% (95% CI 86.8-91.8),
(2)   dysmenorrhea   (n = 602): yes 84.2 (95% CI 81.2-87.2),
(3)   otitis media   (n = 586): yes 77.0% (95% CI 73.5-80.5), and
(4)   allergic asthma   (n = 604): yes 75.5% (95% CI 72.0-79.0).

Table 2

Table 3

North American chiropractors in this survey perform a broad spectrum of clinical services and practices (Table 2).

Given a list of 24 clinical services, procedures, and privileges that are utilized by some chiropractors, a majority of the respondents deemed 21 of them to be “appropriate for the chiropractic profession’s scope of practice” (Table 3). Before reviewing the list of 24 services, the respondents were instructed to assume that any chiropractor who would choose to offer one of the services would have received “adequate training.”

Except for a few jurisdictions in the world, chiropractic has traditionally presented itself as a drugless, nonsurgical health care profession. Given this background, it is not surprising that North American chiropractors, as a group, are of the opinion that only 39.8% of all pharmaceutical prescriptions filled annually are clinically beneficial. Yet, a slight majority (54.3%) think chiropractors should be permitted to write over-the-counter (OTC) prescriptions. On the other hand, a slight majority (51.2%) oppose the proposition of chiropractors writing prescriptions for musculoskeletal medicines (e.g., muscle relaxants). Finally, an overwhelming majority (88.6%) oppose chiropractors writing prescriptions for any and all medicines, including controlled substances.

      Bivariate Findings

Chiropractors with the smaller practices were significantly more supportive of the right to prescribe OTC medicines: 60.7% of smaller (≤99 visits weekly) practitioners favored the right to prescribe OTC medicines, in contrast to 48.9% of moderately sized (100-149 visits) practitioners, and 50.3% of large (≥150 visits) practitioners (p < 0.05).

Respondents who see smaller numbers of patients also differ on the results they report from the spinal adjustment. In acute mechanical lumbar cases, the practitioners were asked to rate the spinal adjustment on an effectiveness scale of 0 (no benefit) to 10 (great benefit): the small practitioners rated the adjustment at 8.8, while in contrast the moderate and large practitioners rated the adjustment at 9.2 and 9.3, respectively (p < 0.05).

While 69.8% of the smaller practitioners found the adjustment usually elicits improvements in allergic asthma, in contrast, 77.8 and 83.6% of the moderate and large practitioners found the adjustment usually elicits improvements in the same type of asthma (p < 0.05).

Nearly one-fourth of the respondents had not been treated by a chiropractor before entering chiropractic college. These respondents rated the effectiveness of the adjustment in typical acute mechanical lumbar cases as being 8.7 (10-point scale), while others in the survey rated it as 9.1 (p < 0.01). Similarly, of those who had not been a chiropractic patient before entering chiropractic school, 68.1% found the adjustment usually improves allergic asthma cases, while 78.0% of the other respondents usually found improvement in these cases (p < 0.01).

Using the three largest alumni groups in order to minimalize sampling error, the respondents who attended National (n = 63) had the highest proportion who self-labeled themselves as broad scope (57.1%), while Palmer (Davenport) (n = 148) had the highest proportion who labeled themselves as middle scope (55.1%), and Life (Marietta) (n = 69) had the highest proportion who chose the focused scope designation (31.9%) (p < 0.01).

There was a statistically significant relationship between the self-rated scope of practice findings and each of the 10 dependent variables used in the bivariate analyses. This means that the 9-point scope of practice scale and the accompanying definitions (broad scope, middle scope, and focused scope), taken together, constitute a powerful scope of practice index. The most dramatic statistical association in the entire survey was between the responses on the scope of practice scale and the responses on the question of whether chiropractors should be permitted to prescribe OTC medicines. Among broad scope respondents, 77.1% indicated yes, while 53.5% of the middle scope and 17.6% of focused scope respondents answered yes (p < 0.01).


One word that summarizes the findings of this survey: consenus. Rank and file chiropractors of North America line up in supermajorities (>75%) to endorse the following key concepts:

1.   The appropriateness of a broad spectrum of conservative clinical services,
practices, procedures, and privileges

2.   The term vertebral subluxation complex

3.   The subluxation as a significant contributing factor in many visceral ailments

4.   The adjustment as an effective treatment procedure for both musculoskeletal
and selected visceral conditions

5.   The differential diagnosis

6.   The concept of maintenance/wellness care

7.   The teaching of a relationship between spinal subluxations and visceral health

8.   The counseling of patients in stress reduction and ergonomics

Middle scope chiropractors endorse the above eight concepts. Even majorities of both broad scope and focused scope respondents register support for each of these concepts.

Despite the fact that the respondents overwhelmingly endorsed the term vertebral subluxation complex, some chiropractors continue to criticize the terminology on several counts. One complaint is that the profession sows confusion by giving this medical concept a decidedly chiropractic twist. When orthopedists say subluxation, they mean an acute overriding of vertebral facets. Chiropractors, on the other hand, often use the term to denote a fixation and/or slight off-centering of one vertebra with another.

This fixation has traditionally been viewed by the profession as causing sensory and motor nerve disturbances, as well as sometimes contributing to altered autonomic activity, hence, disposing patients to illness and visceral dysfunction. Because this autonomic hypothesis is primarily empirically based, some chiropractors argue it should not be presented to patients.

Despite these very real concerns, the one-sided response from the chiropractors in this survey indicates that, from the perspective of field practitioners, the term vertebral subluxation complex is more of a unifying term than it is a divisive one.

The question “Should the adjustment be limited to musculoskeletal conditions?” is rejected by a 9 to 1 ratio and stands as another indication that large numbers of chiropractors hold the view that in select cases they have the clinical potential to influence visceral conditions by adjusting the vertebral subluxation.

It should be noted that in this question the term neuromusculoskeletal was rejected for the more succinct musculoskeletal. The term neuromusculoskeletal opens the door for misunderstanding. To some broad scope chiropractors, this term might be interpreted as being concerned only with nerve activity as it relates to the musculoskeletal system. Yet, to some focused scope chiropractors, the prefix neuro might suggest both peripheral and autonomic nerve activity, with the latter relating to the physiology of internal tissues.

While large majorities of the survey subjects indicated they usually elicit improvements by rendering spinal adjustments in four specific conditions (migraines, dysmenorrhea, otitis media, and allergic asthma), it must be remembered that the above results are based on the respondents’ general perception of the clinical outcomes. Personal clinical experience, obviously, is not the same as controlled clinical studies. Instead of proving that adjustments benefit internal conditions, these data simply document that large proportions of the respondents believe that their adjustments have been effective with select internal ailments.

Given the profession’s prevailing attitude that a majority of prescriptions are not clinically beneficial, why would approximately half of the survey subjects favor limited (over-the-counter and musculoskeletal) prescription rights? The typical North American chiropractor cannot write prescriptions, including OTC medicines. This causes a problem not only for the chiropractor who would like to prescribe OTC medicines, but it also causes a problem for the practitioner who wants to get patients off the chronic use of some OTC drugs (e.g., long-term use of Ibuprophen causing rebound pain). It is the legal right to prescribe a class of medicine that conveys the legal right to manage that same class of medicine. Therefore, even the chiropractors who are opposed to pharmaceuticals and wish only to counsel patients against OTC medicines may find themselves arguing for limited prescription rights.

The fact that 93.4% endorse the differential diagnosis at new patient examinations is a clean break with the old proposition that chiropractors should eschew all diagnosis in favor of analyzing the spine for subluxations only. This finding, when combined with the 74.2% who endorse hospital admitting privileges, indicates that most in the profession no longer narrowly define themselves in opposition to medicine.

The findings of this survey clearly suggest that the profession needs to review and modify century-old stereotypes. Most broad scope practitioners endorse the subluxation and its somatovisceral implications. Most focused scope practitioners routinely perform a differential diagnosis and offer exercise recommendations.

The profession probably needs to more fully appreciate the fact that nearly one-half of the respondents choose to place themselves near the middle of the scope of practice scale.

Within the focused scope camp, particularly among the more tradition-bound practitioners, there is a need to appreciate the fact that the profession soundly rejects the old notion that chiropractic should restrict itself to the adjustment of the subluxation. These same chiropractors, however, can be cheered by the fact that field practitioners clearly acknowledge the contribution of the vertebral sublxuation to a majority of visceral ailments. Still, this empirically based proposition will never move from the realm of philosophy to science until research findings sanction the move.

Within the broad scope camp, especially among the more doctrinaire practitioners, there is a need to appreciate the fact that, while great numbers of chiropractors believe the subluxation contributes to visceral ailments, they are not creedalists. As a group, the respondents hold that the subluxation contributes to approximately 6 of 10 visceral conditions, not 9 of 10 as may have been the case in the early 1900s. Otherwise, these same broad scope practitioners can celebrate that the profession clearly endorses the appropriateness of a board spectrum of clinical services.

The one item that appears to divide chiropractors involves limited prescriptions rights, be it over-the-counter medicines or musculoskeletal pharmaceuticals. Even this issue may be dampened by the profession’s overall skepticism as to the clinical benefits of medicines; only 39.8% of all prescriptions are viewed as beneficial.

One weakness in this study is that intensity of attitudes is not measured. This was planned. The object was to limit the survey instrument to one legal sheet, printed front and back, so as to maximize the response rate.

Another weakness centers on the patients-treated-perweek response category of 99 or less. Since almost 46% of the respondents checked off 99 or less as the amount of patients they personally treat each week, there is a clear need to create a lower category. One possibility would be 49 or less.

The results of this survey suggest that North American chiropractors are not only in consensus on many issues, but are less defensive, less absolutist, and less polemic than the stereotype. The data also indicate that chiropractors know they offer patients a valuable service. The picture emerging from this survey is of a confident, pragmatic, and discerning profession, more capable than ever of participating in an interdisciplinary health care environment.


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