Consumer Decisions to Reduce Or Stop Using Products and Services: Preliminary Results of a Nationwide Study

Douglass K. Hawes, University of Wyoming
Roger D. Blackwell, The Ohio State University
W. Wayne Talarzyk, The Ohio State University
ABSTRACT - That sphere of consumer behavior involving the decision to cease or reduce consumption of a product or service has been essentially neglected in the published literature. It is apparently assumed that once a consumer becomes brand- or store-loyal, he or she will remain in that category (with some stochastic departures) ad infinitum.
[ to cite ]:
Douglass K. Hawes, Roger D. Blackwell, and W. Wayne Talarzyk (1976) ,"Consumer Decisions to Reduce Or Stop Using Products and Services: Preliminary Results of a Nationwide Study", in NA - Advances in Consumer Research Volume 03, eds. Beverlee B. Anderson, Cincinnati, OH : Association for Consumer Research, Pages: 102-109.

Advances in Consumer Research Volume 3, 1976      Pages 102-109

CONSUMER DECISIONS TO REDUCE OR STOP USING PRODUCTS AND SERVICES: PRELIMINARY RESULTS OF A NATIONWIDE STUDY

Douglass K. Hawes, University of Wyoming

Roger D. Blackwell, The Ohio State University

W. Wayne Talarzyk, The Ohio State University

ABSTRACT -

That sphere of consumer behavior involving the decision to cease or reduce consumption of a product or service has been essentially neglected in the published literature. It is apparently assumed that once a consumer becomes brand- or store-loyal, he or she will remain in that category (with some stochastic departures) ad infinitum.

This paper outlines several possible loyalty reduction or cessation situations which have not been addressed in the research literature. The results from part of a nationwide study of 2000 married consumers' participation in, and attitudes toward, leisure time pursuits dealing with this problem are discussed.

In an era of exploding new household formations and unlimited resources to produce new products, consumer research and marketing strategy usually focused on how to attract new customers to new products. As that era ends, consumer research must increasingly focus on the issue of market retention as well as market growth.

Many questions emerge when considering market retention strategies which may he answered by consulter research. What types of products or services are most frequently abandoned by consumers? [The term "product" is used in this paper in the Kotterian sense of physical object, service, person, place, organization or idea.] What are the distinguishing demographic, lifestyle, and attitudinal characteristics of consumers who reduce or cease consumption of a product category or of a brand within a product category? What are the circumstances that lead to the transition from consumption to reduced or ceased consumption? What are the reasons given by consumers for ceasing or reducing consumption of a product category or of a brand within a product category?

This paper reports preliminary results of a study of one type of consumer decision--the decision by consumers to stop or reduce their participation in leisure time pursuits. The study is exploratory, focused upon services rather than tangible products, and confined to one type of decision. It may well provide insights, however, into the general topic of disconsumption--an area of consumer decision making which has received scant attention in the consumer behavior literature.

Specifically, this study seeks to answer the question:

What are the characteristics of persons who reduce or stop consumption of leisure time pursuits, and what are the reasons for the reduction or cessation of consumption?

BACKGROUND OF THE STUDY

There has been little published research on the reasons why consumers cease to use a brand or product, but there has been considerable research on the topic of brand and store loyalty. Some of this literature is helpful in providing a framework for the analysis of product or brand disloyalty.

An overview of the topic of brand loyalty is found in Consumer Behavior, Second Edition (Engel, Kollat, Blackwell, 1973). A number of journal articles have also surveyed the field (Horton, 1973; Sheth, Park, 1973), particularly the pros and cons of various models of brand choice behavior (Aaker, 1972; Bass, 1974; Blattberg, San, 1973; Charlton, French, 1972; Ehrenberg, Goodhardt, 1970; Herniter, 1973; Jones, 1970; Jones, 1970; Jones, 1973; Kraft, Granbois, Summers, 1973; Montgomery, 1968; Schendel, Summers, Weiss, 1968; Sheth, Park, 1973). Finally, several studies have suggested focusing attention on specific categories of input variables as means to a better understanding of brand loyalty (Carmen, 1970; Chance, French, 1972; Cohen, Houston, 1972; Newman, Werbel, 1973; Weber, Han-sen, 1972).

This review of the literature supports the inferences drawn above, that interest in the topic of brand loyalty (of "brand consistent behavior") (Kallick, Nearby, Shaffer, 1973), as a form of repeat purchasing behavior (Jacoby, Kyner, 1975; Tarpey, 1974), has been heavily "front end loaded." That is, emphasis has been primarily on (1) the development of brand loyalty, either single brand or (more recently) multi-brand (Ehrenberg, Goodhardt, 1970; Olson, Jacoby, 1973; Sheth, Park, 1973), (2) those characteristics distinguishing brand-or store-loyal consumers from non-loyal consumers (Carmen, 1970; Lessig, 1973), and (3) distinguishing higher--frequency purchasers of products from lower-frequency purchasers (Barker, Trost, 1973; Wheeler, 1973). Downstream maintenance marketing strategies aimed at retaining currently loyal consumers (Kotler, 1973) in the face of efforts by competitors to cause brand- or product-type switching have not been researched.

While brand loyalty/repeat purchase behavior and its correlates have been studied intensively, published research indicates almost no interest in usage reduction/cessation. In previous research, interest ceased when the consumer crossed that threshold into the "brand-loyal" (or "store-loyal") category for a product-type. An assumption in these models, it would appear, is that once a consumer becomes "brand-loyal," he will remain in that category (with some stochastic departures) ad infinitum.

Little attention has been directed to the following schematized situation:

......A-A-B-C-A-B-A-A-A-A-A.........

                                    Initial trial of brand A of prod. type X                              "Loyal" to brand A

A-A-D-A-A-D-A-D-D-D-D-D-D.......etc.

                                                Loyalty transition region                          "Loyal" to Brand D of prod. type X

Examples of this situation would be switching from one brand of pantyhose to another, or, in store-patronage loyalty terms, the downhill skier shifting loyalty from one ski area to another (from Aspen to Vail, for instance).

Similarly, even less attention has been given to the problem of product-type switching, let alone brand switching within the product category. Product-type switching over time might be schematically illustrated as follows:

......Ax-Ax-Bx-Cx-Ax-Bx-Ax-Ax-Ax.......

                                    Initial trial of brand A of prod. type X                              Loyal to brand Ax

"x-Dy-Ax-Dy-Dy-Ax-Dy-Dy-Dy-Dy-Dy...

                                                Loyalty transition region                          "Loyal" to Brand D of prod. type Y

An example would be the regular coffee drinker who switches, more or less permanently, to tea drinking--perhaps on doctor's orders. Similarly, the blended whiskey (or scotch) drinker who switches to wine would be a case in point, as would be the hobbyist who switches from stamp to coin collecting or the tennis player who switches to golf.

Considerable attention has been given to the heavy-versus-light user problem, and how to (hopefully) move light users into the heavy-user category, Kotler and Levy (1971) have also discussed the situation of "intentionally'' moving users back into the light-user category through demarketing efforts. Few studies have addressed the problem of the heretofore "heavy" user who, in spite of efforts to keep him in that category reduces his consumption and falls back into the "light half." Schematically, this might be illustrated as follows:

......A-B-A-B-B-A-B-A-A-A-A-A-A-A-

                                    Initial trial of brand A of prod. type X                              Heavy brand loyal user

-A-A--A---A---A----A---A----A-----A------A....

                                                    Transition region                                         Light brand loyal user

As sketched, this consumer (or group of consumers) remains "brand loyal" while reducing his consumption. Obviously, the same type of problem could be exacerbated by a weakening of brand loyalty or even by a total switch to a different brand--perhaps one which in some ways partially compensates for the reduction in product-type usage frequency. Examples here might 5e the heavy alcoholic beverage drinker who prefers "getting on the wagon" slowly rather than "cold turkey," or the golfer who finds himself unable to play as often as he once did.

Finally, the last distinct situation is that of the complete cessation of consumption of the product type or generic product category--schematically,

......A-A-B-C-A-B-A-A-A-A-A-A-A-A-A-A/

                                    Initial trial of brand A of prod. type X                              Loyal to brand A

                                                                                     Cessation of use of prod. type X or generic product category Xx

The previously avid downhill skier or tennis buff who completely stops engaging in the activity is an example. Similarly, the motorcycle devotee or the power boat enthusiast who stops participating in the activity are cases in point. The cigarette smoker or alcoholic beverage drinker who stops "cold turkey" are familiar examples.

RESEARCH METHODOLOGY

The research methodology used in this study involved collecting data on a comprehensive group of leisure-time variables from a representative cross-section of the married United States population. The data encompassed a wide range of leisure-time related variables, in addition to the ones analyzed in this paper.

Data Collection

The instrument used to collect data was a 20-page questionnaire which requested, in addition to other variables, the following information:

1. respondent's participation in leisure-time pursuits in the past and during 1972 (list of 50 pursuits provided);

2. pursuits which had been "completely dropped or stopped" or "reduced" in participation by the respondent during the past 5 years;

3. reasons for stopping or reducing each pursuit listed as "stopped" or "reduced," with up to 5 reasons permitted for each pursuit from a list of 16;

4. demographic variables including respondent's age, education, total household income, occupation, household size end location (rural, suburban, urban).

Other information which was collected included media preferences, extent of agreement with 87 AI0 (Activity, Interest, Opinion) statements expected utilization of additional blocks of non-work time, and recreational equipment ownership. Additional papers will report these data when analysis is completed.

A pre-test of the questionnaire was conducted among married graduate students at The Ohio State University to determine and refine the clarity of the questions. A secondary pre-test was conducted using 85 households in the Columbus, Ohio, area. Numerous modifications were made based upon these pre-test results. The final pre-test was administered to 100 households throughout the United States using the sampling procedure described below.

Sampling Procedure and Response Rate

Two questionnaires were mailed to 1000 households in May, 1973, by Market Facts, Inc. (Chicago, Illinois), from their panel of 45,000 households. Questionnaires for males and for females were sent to households whose names had been recently added to the panel and who had demographic characteristics proportional to the 1970 Census of the United States.

A total of 603 usable female and 512 usable male questionnaires were returned. The gross response rate was 63 percent while the net usable returns totaled 61 percent.

The demographic characteristics of the respondents were very close to the proportions true of the entire United States on geographic region, urbanization, income, and education, and only slightly higher in age than the adult U.S. population. Families with total household income under $4,000 were excluded from the original sample, but incomes of respondents were otherwise similar to the income distribution in the total U.S. population.

RESEARCH FINDINGS

The findings concerning the reduction or cessation of participation in leisure-time pursuits are presented in Tables 1 through 4. A brief commentary on these data is presented below, addressed to the following three questions:

1. What leisure-time pursuits were reduced or stopped?

2. What are the characteristics of consumers who reduced or ceased leisure-time pursuits?

3. What are the stated reasons of consumers for reduction of cessation of leisure-time pursuits?

Pursuits Stopped or Reduced

People are "disloyal" to activities in which they once engaged. Table 1 shows that 46 percent of males and 54 percent of females either reduced and/or stopped participation in some leisure-time pursuits during the preceding five years.

TABLE 1

NUMBER OF RESPONDENTS STOPPING, REDUCING, OR MAINTAINING THEIR PARTICIPATION IN LEISURE TIME PURSUITS

The pursuits most frequently stopped or reduced are listed in Table 2. Only those pursuits listed by at least 15 respondents are included. Perhaps different reasons determine stopping than determine reduction in participation. When the frequency of reduction or cessation is recomputed as a percentage of all consumers involved in a leisure-time pursuit (during 1972), it may be seen that the greatest disloyalty among men (20 percent) is for square dancing or other dancing. Among male who are still involved in a pursuit but who have reduced participation, the highest proportion (19.2 percent) is for golf. A hypothesis that might be advanced is that complete cessation may be more related to liking or disliking of an activity, but that reduction for busy people may be more related to time restraints on participation in the activity.

Most of the pursuits reported stopped or reduced in Table 2 are physically strenuous and out-of-the-home. Perhaps these data indicate a trend toward a stay-at-home, sedentary, physically "soft" society. This is consistent with findings that the favorite leisure pursuits of American consumers are listening to music, visiting with friends, reading, and driving around for pleasure or sightseeing (Hawes, 1973).

TABLE 2

LEISURE TIME PURSUITS MOST FREQUENTLY STOPPED OR REDUCED IN PARTICIPATION

Demographic Characteristics of Disloyal Consumers

Consumers who are "disloyal" to leisure-time pursuits are described in Table 3. That table shows the most significant demographic characteristics of consumers who have stopped or reduced their participation.

Consumers who have reduced or stopped consumption of leisure-time pursuits are "up-scale" demographically. "Disloyal" male respondents tend to be in the 35-44 age group and not in the over-55 group, and tend to be professionals rather than operatives. Females, who stopped/reduced pursuits, tend to be in the highest income category, have attended or graduated from college, are in the 25-34 age group, and do not live in the urban area of SMSA's.

The age and income distributions of respondents indicates that the busy, middle-aged years of affluent families are prime times for cutting back on activities. As people near the retirement age (55 or over), they appear to be more loyal to old, familiar pursuits.

Reasons for Stopping or Reducing Participation

The most frequently reported reasons for reducing or stopping participation in leisure-time pursuits are shown in Table 4. A pattern emerges which is helpful in understanding the decision to reduce or stop participation.

Table 4 shows that among male consumers the most frequent reason for stopping participation are:

1. Just lost interest (153) [Number represents the frequency that the reason was selected across all pursuits which were reduced to stopped.]

2. Don't have enough time anymore (140)

3. Have new, different interests and activities (86)

4. My present family situation makes it difficult to engage in the activity (78)

5. People I used to do the activity with have moved away or lost interest (77)

6. Became too expensive (77)

The reasons for reducing participation which appear in Table 4 are similar:

1. Don't have enough time anymore (205)

2. Just lost interest (143)

3. Have new, different interests and activities (104)

4. My present family situation makes it difficult to engage in the activity (102)

5. Became too expensive (94)

6. People I used to do the activity with have moved away or lost interest (84)

While the rankings of these reasons are similar, the difference is that loss of interest is the most frequent reason for stopping an activity, while the most frequent reason for reducing participation is a perceived time constraint.

Among female respondents, Table 4 reveals that the most frequent reasons for stopping participation are:

1. Don't have enough time anymore (187)

2. My present family situation makes it difficult to engage in the activity (169)

3. Just lost interest (163)

4. Have new, different interests and activities (98)

5. People I used to do the activity with have moved away or lost interest (90)

6. Became too expensive (83)

The reasons given by females for reducing participation also emphasize time constraints:

1. Don't have enough time Anymore (232)

2. My present family situation makes it difficult to engage in the activity (229)

3. Just lost interest (149)

4. Have new, different interests and activities (108)

5. Became too expensive (108)

6. People I used to do the activity with have moved away or lost interest (103)

This is rather compelling evidence that consumers' time budgets are more important in the decision to stop or reduce leisure-time pursuits than are their money budgets. This is compatible with the position recently advanced by Voss and Blackwell (1974) that marketing strategists must analyze buying decisions in terms of the time resources required as well as the money resources. Although the popular press has given much attention to alleged reductions in the work week, it may he that non-work time is so filled with other (non-discretionary) activities that consumers must abandon pursuits or products previously enjoyed because of the competing time pressures.

TABLE 3

DISTRIBUTIONOF RESPONDENTS, BY PARTICIPATION LEVEL CATEGORY, ACROSS SELECTED DEMOGRAPHIC VARIABLES

TABLE 4

LIST OF REASONS FOR STOPPING OR REDUCING PARTICIPATION GIVEN TO RESPONDENT AND OVERALL FREQUENCY OF SELECTION ACROSS ALL 50 PURSUITS

Losing interest in pursuits once enjoyed is also a common experience. This should indicate to marketing strategists the frailty of consumer loyalty for even favored activities. Strategists must continually consider ways to add new dimensions to an activity or to develop new promotions and excitement if the pursuit is not to fade away from the consumers' preferences because of "lost interest."

Several other insights are revealed in Table 4. Males are less deterred by increased travel necessary to continue participation than are females. Accidents and fatigue resulting from participation are also less of a barrier to males than to females. Females, on the other hand, are slightly less discouraged by crowds and unfavorable weather than are males, possibly because of the general female orientation toward indoor activities.

CONCLUSIONS

This study indicates that there are substantial numbers of consumers who "drop out" of markets for leisure time activities. The persons who reduce or stop participation in leisure time pursuits are not primarily older persons no longer physically able to participate, nor poor consumers no longer able to afford participation. Rather, the "pursuit disloyal" consumers are middle-aged, educated, moderately affluent persons.

The reasons for stopping or reducing leisure-time pursuits are not primarily money related. They are, however, related to perceived lack of time and lack of interest--both of which factors can be influenced by innovative marketing strategy.

DISCUSSION

This study deals specifically with consumer decisions concerning services, i.e., leisure-time pursuits. It is recognized that it is not possible to generalize the findings from this study to the entire field of consumer behavior and brand disloyalty. Several suggestions do emerge, however, that may be worthy of further research and conceptual development in an attempt to understand the phenomenon of ending loyalty to a product-type, brand, or retail source.

First, marketing strategists should collect data on cessation and reduction of usage for product categories and specific brands. These data might be reported in a form similar to "lapse rates" in the insurance industry which indicate the proportion of policies which are dropped for all reasons within a time period. Mathematical models could be developed using lapse rates for product categories to indicate the number of new consumers which must be added to retain present volume or to achieve specified growth rates. It should be feasible to develop additional models which balance target growth rates with optimal levels of resource commitment.

Second, reasons for disconsumption should be determined. This type of research should facilitate improved marketing strategies which again might be compared to the concept of "conservation management" in the insurance industry. Conservation management refers to marketing programs designed to retain present customers rather than to develop new customers. For example, if other product categories are similar to the leisure-time pursuits investigated in this study, the necessity of continually creating new interest in an existing of-feting would be critical. Even though the product category is already liked end purchased, the firm may need to adopt a strategy of ':innovate or perish" if it is to maintain high acceptance. A measure of such strategies would be a "persistency ratio," which could be compared across market segments, marketing programs, and marketing organizations.

Third, consumption end disconsumption decisions should be analyzed in a framework which includes time budgets as well as money budgets. It is apparent that within the constraint of consumer money budgets, a decision to purchase one product must cause a decision to reduce or terminate purchases of another (perhaps unrelated) product. This is also true within the framework of consumers' time budgets. A product which "costs" time from the time budget often generates a decision to reduce or terminate "purchase" of another product or service which also involves consumption of time. Money budgets have no theoretical upper limits, rise very high for some families, have generally increased during recent decades in the United States, and can be temporarily expanded through the use of credit. Time budgets, however, cannot be expanded beyond 24 hours a day or 365 days a year. Time constraints may therefore provide more reasons for understanding disconsumption decisions of some types than have heretofore been recognized.

Finally, analysis of disconsumption decisions may have important dimensions in a demarketing program either for private firms or for government programs. In an age of scarcity of resources, private business firms may wish to move consumers of a product category into non-consumption mode. The firm usually wishes to undertake such a move, however, with the optimal amount of goodwill toward the company, so that the consumer may later begin repurchasing the product or move to substitutes which minimize the firm's losses. Similarly, the government may be in the position of undertaking demarketing programs for gasoline consumption or energy-intensive forms of leisure activities. In either situation, it becomes essential to understand the consumer processes involved in ceasing or reducing use of a product or service formerly preferred.

REFERENCES

David A. Aaker. "A Measure of Brand Acceptance," Journal of Marketing Research, 9 (May, 1972), 160-167.

Stephen M. Barker and 3ohn F. Trost. "Cultivate the High Volume Consumer," Harvard Business Review, 51 (March-April, 1973), 118-122.

Frank M. Bass. "The Theory of Stochastic Preference end Brand Switching," Journal of Marketing Research, 11 (February, 1974), 1-20.

Stewart W. Bither and Stephen J. Miller. "A Cognitive Theory View of Brand Preference," Proceedings. Fall Conference, American Marketing Association, 1969, 280-286.

Robert Blattberg and Subrata Sen. "Are Stochastic Brand Choice Models Useful Approximations of Buyer Behavior," Proceedings. Combined Fall and Spring Conferences, American Marketing Association, 1973, 241-245.

James M. Carmen. "Correlates of Brand Loyalty: Some Positive Results," Journal of Marketing Research, 7 (February, 1970), 67-76.

William A. Chance and Norman D. French. "An Exploratory Investigation of Brand Switching," Journal of Marketing Research, 9 (May, 1972), 226-229.

P. Charlton and A. S. C. Ehrenberg. "McConnell's Experimental Brand Choice Data," Journal of Marketing Research, 10 (August, 1972), 302-307.

Joel B. Cohen and Michael J. Houston. "Cognitive Consequences of Brand Loyalty," Journal of Marketing Research, 9 (February, 1972), 97-99.

Herbert E. Echelberger and Elwood L. Shafer, Jr. "Snow + (X) = Use of Ski Slopes," Journal of Marketing Research, 7 (August, 1970), 389-92.

A. S. C. Ehrenberg and G. J. Goodhardt. "A Model of Multi Brand Buying," Journal of Marketing Research, 7 (February, 1970), 77-84.

James F. Engel, David T. Kollat, and Roger D. Blackwell. Consumer Behavior, Second Edition. New York: Holt, Rinehart, and Winston, Inc., 1973.

Douglass K. Hawes, W. Wayne Talarzyk, and Roger Black-well. "Consumer Satisfactions from Leisure Time Pursuits,'' Proceedings. Advances in Consumer Research, Vol. 2, Association for Consumer Research, 1974.

Jerome D. Herniter. "An Entropy Model of Brand Purchase Behavior," Journal of Marketing Research, 10 (November, 1973), 361-375.

Raymond L. Horton. "On the Appropriateness of Brand Choice and Brand Loyalty and Dependent Variables in Consumer Personality Studies," Proceedings. Southern Marketing Association, 1973, 147-151.

Jacob Jacoby and David B. Kyner. "Brand Loyalty vs. Repeat Purchasing Behavior," Journal of Marketing Research, 10 (February, 1975), 1-9.

Kenneth L. Jensen. "Purchase Frequency and Consumer Perceptions of Marketing Variables," Proceedings. Southern Marketing Association, 1973, 86-91.

J. Morgan Jones. "A Dual Effects Model of Brand Choice," Journal of Marketing Research, 7 (November, 1970), 458-465.

J. Morgan Jones. "A Comparison of Three Models of Brand Choice," Journal of Marketing Research, 7 (November, 1970), 466-473.

J. Morgan Jones. "Testing Probability of Purchase Distribution and Ad Hoc Market Segmentation Schemes," Proceedings. Combined Fall and Spring Conference, American Marketing Association, 1973, 246-249.

Maureen Kallick, Joseph Nearby, and Jay Shaffer. "The Dimensions of Brand Consistent Behavior," Proceedings. Advances in Consumer Research, Vol. 1, Association for Consumer Research, 1973, 460-462.

Philip Kotler and Sidney 3. Levy. "Demarketing, Yes, Demarketing," Harvard Business Review, 49 (November-December, 1971), 74-80.

Philip Kotler. "The Major Tasks of Marketing Management,'' Journal of Marketing, 37 (October, 1973), 42-49.

Frederic B. Kraft, Donald H. Granbois, and John O. Summers. "Brand Evaluation and Brand Choice: A Longitudinal Study," Journal of Marketing Research, 10 (August, 1973), 235-241.

V. Parker Lessig. "Consumer Store Images and Store Loyalties," Journal of Marketing, 37 (October, 1973), 72-74.

Jerry C. Olson and Jacob Jacoby. "Measuring Multi Brand Loyalty," Proceedings, Advances in Consumer Research, Vol. 1, Association for Consumer Research, 1973, 447-448.

Joseph W. Newman and Richard A. Werbel. "Multivariate Analysis of Brand Loyalty for Major Household Appliances,'' Journal of Marketing Research, 10 (November, 1973), 404-409.

David B. Montgomery. "Stochastic Consumer Models: Some Comparative Results," Proceedings. Fall Conference, American Marketing Association, 1968, 409-415.

Morris Rosenberg. The Logic of Survey Analysis. New York: Basic Books, 1968.

Dan E. Schendel, John O. Summers and Doyle L. Weiss. "Simulation and Model Testing," Proceedings. Fall Conference, American Marketing Association, 1968, 416-429.

Jagdish N. Sheth and C. Whan Park. "A Theory of Multidimensional Brand Loyalty," Proceedings. Advances in Consumer Research, Vol. 1, Association for Consumer Research, 1973, 449-459.

Lawrence X. Tarpey, Sr. "A Brand Loyalty Concept--A Comment," Journal of Marketing Research, 11 (May, 1974), 214-217.

Justin L. Voss and Roger D. Blackwell. "Markets for Leisure Time," Proceedings. Advances in Consumer Research, Vol. 2, Association for Consumer Research, 1974.

Jean F. Weber and Richard W. Hansen. "The Majority Effect and Brand Choice," Journal of Marketing Research, 9 (August, 1972), 320-323.

David R. Wheeler. "Brand Switching Behavior of 'Heavy' and 'Light' Product Users," Proceedings. Southern Marketing Association, 1973, 135-140.

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