Measuring the Impact of Health Awareness on Food Demand

H. H. Jensen; T. Kesavan; S. R. Johnson

Review of Agricultural Economics, Vol. 14, No. 2. (Jul., 1992), pp. 299-312.

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MEASURING THE IMPACT OF HEALTH AWARENESS ON FOOD DEMAND

H.H.Jensen, T. Kesavan, and S.R. Johnson

Diet and health attitudes affect food consumption behavior. T h e National Dairy Board provided information on the benefits o f calcium and dairy products in a 1985-86 national advertising campaign. A latent variable measuring consumer attitudes, constructed based on an ad tracking survey, is shown t o have a positive effect on both the probability of dairy product purchaseaswell a s the quantity of dairy products purchased. T h e consumption data were from the USDA "Continuing Survey of Food Intakes by Individuals."

Introduction

In recent years, food industry groups, consumer and health groups, producer organiza- tions, and government agencies have paid considerable attention to the health-related aspects of foods. Both food manufacturers and farmer organizations have capitalized on increased evidence of diet-health linkages by disseminating information about health-related product characteristics and product quality. Examples include high fiber cereal products, foods with oats ingredients, calcium in dairy products and orange juice, low-fat meats, and no cholesterol salad dressings.

Dairy products are an excellent calcium source and have been promoted by nutrition educators as an important component of a healthful diet. In 1985 the National Dairy Promotion and Research Board (NDPRB)

T h e authors a re Associate Professor, Adjunct Assistant Professor, and Professor, respectively, Center for Agricultural and Rural Development and Department of Economics, Iowa State University, Ames, Iowa. Marvin Hayenga and an anonymous reviewer provided useful comments on earlier versions of this paper. T h e authors acknowledge the financial support provided by theNational Dairy Research and Promotion Board and the data provided by Market Facts, Inc. T h e views expressed a re solely those of the authors. Journal Paper No. J-14518 of the Iowa Agriculture and Home Economics Evperiment Station, Ames, Iowa; Project No. 2806.

launched an advertising campaign informing consumers about the benefits of calcium and of calcium in dairy products, thus promoting milk and its products. At a cost of nearly $12 million dollars annually, the NDPRB initiated a broad national promotional program in both television and print media emphasizing the calcium content of milk and other dairy products.

Does such information about a product's nutritional o r health characteristics affect demand? Although advertising and changes in nutrient information have been integrated into demand models (see Capps and Schmitz for a review), there is limited-;conomic analysis o n the mechanism of change o r the net impact. The interaction among information, health- related attitudes, and food demand is not well understood. Yet understanding these linkages is needed both for determining the relative effect of generic food advertising and for developing effective nutrition education programs. T o a great extent, the lack of reliable health infor- mation o r awareness indicators has limited the ability to identify and measure the impact of health and nutrition information on food demand.

Several recent studies using aggregate time series data have included a time trend o r proxy indicator to reflect changes in consumers' tastes and preferences (e.g., Brown and Schrader; God-dard and Arnuah). The difficulty in such studies usually lies in associating the observed temporal change in behavior with the specific cause.

Cross-sectional consumption surveys, sometimes conducted in more than one time period, provide another source of data for explaining changes in consumption patterns (e.g., Ippolito and Mathios; Popkin et a].; West and Price). Studies using cross sectional data, such as the USDA "Nationwide Food Consumption Surveys" (NFCS) (Rizek) and the "Continuing Survey of Food Intake for Individuals" (CSFII) (U.S. Department of Agriculture), have

300 REVIEW OF AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

demonstrated the importance of socioeconomic and demographic characteristics, including education, for explaining differences in consumption levels. For example, evidence from two periods of data has been used to identify behavioral changes associated with changing tastes and preferences, changes in demographics (Popkin et al.), o r increased information (Ippolito and Mathios). Such evidence is limited, however, in its ability to measure consumer attitudes and, hence, the mechanism of change.

This article provides an alternative approach to using such "indirect" evidence by merging information about consumer attitudes towards calcium based on a consumer attitude survey with an analysis of demand for dairy products basedoncross-sectional consumption survey data. Since survey data are costly, and often gathered for different purposes, two different, but relatively common types of data were used to provide a more comprehensive analysis of existing data. The ability to link data sets provides a means of incorporating measures of consumer attitudes directly into demand functions and of testing hypotheses about the influence of health and nutrition information o n consumer demand for dairy products. The identificationof consumer attitude and health awareness measures is not directly observable and their construction and effect on observed consumer behavior are key concerns.

The article is organized as follows. First, an empirical framework is formulated that relates the effects of consumer attitudes and awareness on product demand. The next section describes the calcium advertisement tracking study and discusses the construction of attitudinal indices. The relation of these attitudinal indices tosocioeconomiccharacter-istics forms the basis of linking attitude measures to the CSFII consumption data. Next, the empirical model is applied to dairy product data from the CSFII. The instrumental variables utilized in this study are basedon theestimated coefficients from the calcium advertisement tracking data. The influence of the selected variables is then tested under a two-step demand model. The final section includes a summary and discussion of implications.

Empirical Approach

Consider a Marshallian demand function for the commodity qi:

where qi is the quantity consumed, pi is the price of commodity i, Y is income, and Z is the set of socioeconomic variables related to the consumer. Consumer preferences may depend upon perceived product quality o r "usefulness" of the product. The effect of health and nutrition information about product characteris- tics on demand is through the awareness of the product characteristic (e.g. Swartzand Strand). Thus, information can be incorporated explicitly into the demand function (1) by augmenting the function to include the variable I:

The relation between the information1 attitude variable (I) and the demand for the product can be positive o r negative, depending upon the type of information o r attitude. For instance, the information that dairy products have calcium and the belief that calcium is good for general well-being are expected to have a positive influence (upward shift) on the demand for dairy products. O n the other hand, the information that fat content in dairy products is high would be expected to have a negative effect (downward shift) on their demand.

The role of information has been studied extensively in the context of product demand (e.g., Kotowitz and Mathewson; Khilstrom; Pope). These studies show that information allows consumers to make better decisions about consumption and is valuable to consumers. In this respect, the inclusion of an information variable in the demand equation (2) reflects the hypothesis that health and nutrient information will alter consumers' attitudes; and hence, affect product demand. Such a notion is often recognized explicitly in both marketing and psychological literature (McEwen). The

MEASURING THE IMPACT OF HEALTH AWARENESS Jensen, Kesavan, Johnson 301

important empirical question for demand analysis is to identify the effect of changing consumer awareness on product demand.

Changes in consumer information o r attitudes can be inferred from two observable changes in product demand. First, changing information and attitudes affect the probability that consumers will purchase the product. This is the premise underlying surveys that track frequency of purchase data. Monitoring changes in frequency of purchases provides a means for evaluating the success of advertising or information programs.

The second effect is the induced effect on demand (quantityconsumed) for those individ- uals already consuming the product. Thus, health-related informationshould beevaluated for its effect both on the likelihood of purchase and on the conditional demand for the product.

This formulation provides the empirical structure for the testing of hypotheses about variables related to consumer attitudes and awareness in this study. Advertising about cal- cium in dairy products is used as an example in order to evaluate the effect of changing attitudes and health awareness on demand for dairy products. The evaluation includes whether or not both the likelihood of purchase and the level of consumption for dairy products are changed. Corresponding to the two effects, a two-step demand model is adopted to evaluate the impact of changing consumer attitudes and awareness on demand.'

The conceptual model consists of two equations:

pr(qi>0) = g(pi. Zl , Y. I, eli) and (3)

where qi refers to quantity consumed, pi indicates price of the commodity, Z1 and Z2 indicate sets of socioeconomic factors, I is the measure of attitude and health awareness, Y

'~l ternat ive l~ ,one could adopt a tobit model and derive theeffect of awarenesson the likelihoodof purchase and intensity of consumption based on Moffitt's decomposi- tion. However, as Haines et al. have concluded based on an empirical study, a two-step procedure may be better suited for food consumption analysis.

indicates household income, and eli and ezi reflect associated disturbance terms.

One important problem arises in estimating equations (3) and (4).The consumers' attitudes and awareness are psychological measures and are not directly observed. Thus, the variable I has to be replaced with a latent variable, I*, which measures the unobserved awareness. The proper specification of the consumer's expectations about the product characteristic is an important part of the empirical estimation problem.

The acquisition of consumer awareness on the health-related product characteristic (calcium) is postulated to be exogenous to the consumer's decision-making process.2 The underlying changes in perceptions and attitudes can be associated with sociodemographic and environmental variables (e.g., McEwen). Accordingly, the attitudes were specified through a logistic function, as:

P(I*) = exP (BZ) + e3,1+ exp (BZ) (5)

where I* is the latent variable measuring attitudes with value between 0 and 1,where 1 expresses positive and 0 negative attitudes; Z represents the socioeconomic and personal characteristics of individuals; B is the vector of parameters to be estimated; and e3 is the disturbance term.

Once the relation between Z and P(I*) isestablished, the estimated parameters, B, can be used to construct an instrument for the latent consumer attitude or awareness variable based on the Zsocioeconomic variables. This approach is analogous to that used in incorporating expectations in economic models (see Pagan for details). Because the logistic transformation used for the attitude variable is asymptotically normal, equations (3) and (4) can be estimated through a two-step maximum likelihood pro- cedure (Maddala). This procedure involves

%he term exogenous implies that individuals' attitudes are formed first before actual decisions about purchases are made. In some cases,consumers may experiment before, and update, their beliefs and attitudes about the product. Although the process of information acquisition may be endogenous within the consumer decision-making process, for empirical tractability, exogeneity was assumed here.

302 REVIEW OF AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

estimating the likelihood of demand (equation 3) through a probit procedure and the demand for products (equation 4) through ordinary least squares methods. This approach is followed here.

Measurement of Consumer Attitude and Health Awareness

Calcium Advertising and Data

As part of the Dairy Board's ongoing management of its advertisement campaigns, data on advertising exposure, awareness, and attitudes about calcium were collected from a calcium advertisement tracking (CAT) survey. This CAT survey, conducted from November 1985 through October 1986 and again from November 1986 through October 1987, was conducted by Market Facts, Inc. under contract with the National Dairy Board. It included a nationwide telephone survey of households. The survey was designed to gather information on dairy food consumption (frequency), attitudes, and beliefs related to calcium intake and health, and o n dairy advertising awareness. The empirical sample was for 2,9% women between the ages of 18 to 54, comprised of 1,706 women from November 1985 through October 1986 and 1,290 from November 1986 through October 1987. Construction of the attitude indices used in this study was based on this data set.

Construction of Indices

Because consumers' attitudes and awareness regarding nutrition and health are observed indirectly, the responses to several selected questions were combined to construct index measures of consumers' awareness and attitudes towards health and calcium.

Frequently, factor analysis o r other forms of latent variable models are applied to construct indices about unobservable phenomena through observed responses (see Aigner et al. for details). Approaches based on factor analysis depend on the variations of the manifest variables and on a normality assumption (Everitt). A major problem encountered in constructing factor indices here, however, was the structure of the survey questions themselves. For many questions in theadvertisement track-

ing survey, the modal value of the response to questions was near the extreme.

As a consequence, several indicators that used scoring procedures were developed (Carmines and Zeller). The underlying moti- vation for such an approach was to make effective use of the existing variation in the survey, to strengthen the interpretation of the attitudes measures, and to overcome the under- lying normal distributional assumptions needed for applying the factor analysis model.

Two categories of questions formed the basis for developing such indices. The first category related to questions on the importance of nutrients for consumers' health (referred to as the "importance" category). The second category was concerned with whether consumers agreed o r disagreed about the dairy product characteristics (referred to as the "Agree/ Disagree" category). These questions were selected on the basis of exploratory factor analysk3

T o - clarify the interpretation of the responses to the survey questions, some modifications were made to the data. Responses initially coded as "no response" (O), "yes" ( I ) , and "no" (2) were converted to "no o r no response" (0) and "yes" (1). Individual responses to agreementldisagreement questions, recorded on a scale of 1 to 10, were reverse scaled for some questions to maintain consistency in interpreting positive attitudes about dairy products. The importance questions were recorded on a scale from 1 to 4. The questions related to awareness o r beliefs about calcium and dairy foods in the advertisement tracking survey are listed in Table 1.

Measures of attitude and awareness based on the modal values of the responses were constructed. Specifically, a binary variable was created for each of the questions, taking a value of one if the response was at or above the modal value, o r zero otherwise. This is akin to scaling the responses for the questions in a binary code. An attitude index towards nutrients was mea- sured through the sum of these binary variables related to questions in the "importance" category

30nly those factors with a loading of 0.25 were retained for subsequent analysis. A copy of these results is available from the authors.

MEASURING THE IMPACT OF HEALTH AWARENESS Jensen, Kesavan, Johnson 303

Table 1. Description of Variables from Calcium Ad Tracking Survey, 1985-87

Description Mean S.D. Min Max

Importance of: Protein Zinc Carbohydrates Calcium Riboflavin Vitamin D Potassium

Agree: Dairy products provide nutrients Dairy products too fattening Not getting enough calcium Too much bother getting calcium from dairy Dairy more nutritious/calories Females need dairy products - calcium Milk is a better calcium source Dairy have too much calcium Best not to take calcium supplements Never outgrow calcium need

Income: Under $15,000 $15,000 - $24,999 $25,000 - $39,999 $40,000 and over Don't know

Source: Market Facts, Inc., Calcium Ad Tracking Survey, 1985-86, 1986-87 (women 18-54).

(SCIMP). Because there were seven questions DSCIMP = 1 if SCIMP 2 mode (i.e., 5 ) , in this category, SCIMP had a potential maxi- 0 otherwise; and mum value of seven. Similarly, consumers' awareness towards health was measured by the

DSCAGR = 1 if SCAGR r mode (i.e.,

sum of the binary variables related to questions 3), 0 otherwise

in the "agree/disagreen category (SCAGR). The and a third index, DIMPAGR, was constructed maximum potential value for this indexwas 10 as: for a positive response relative to the value of

DIMPAGR = 1 if SCIMP 2 mode and calcium for the 10 questions in this category. SCAGR 2 mode, 0 otherwise.

These indices represented consumers' perceptions and attitudes towards nutrition and These three indices formed the basis of health. While these indices can be used directly, subsequent analysis. The DIMPAGR index indices were also transformed into binary measured the aggregate consumer attitude measures which better reflected the distribution- towards health and calcium (I*), evaluated as al characteristics of the (latent) information the interaction between the "importance index" content. Again, a modal criterion was used as (DSCIMP) and the "agreement" index follows: (DSCAGR). Again, the value of one indicates

304 REVIEW O F AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

a more positive attitude about the importance of calcium and dairy products in the diet. The descriptive statistics for these indices are presented in Table 2.

Analysis of Indices

First, factors associated with the indices were evaluated, by estimating equations explain- ing the three selected scored indices as functions of sociodemographic variables and time. The time variable was introduced in quadratic form in order to allow for any nonlinear effects of increased availability of health information. Moreover, to capture the changes in information content in the survey itself (which had been changed once during the ad period), a dummy variable was included to distinguish between the early and later ad periods (DUM8687). Based on equation (5), the attitude and aware- ness index (P(I*))was estimated according to logit procedures.

The estimated logit results for the relation of personal characteristics and time with the three attitude indices are presented in Table 3.

As expected, some socioeconomic charac- teristics were better predictors than others for the indices reflecting attitudes toward calcium. For instance, older women were more likely to hold strong "attitudes" on the importance of nutrients; those with more education also had more positive "attitudes". The coefficient for the dummy variable, DUM8687, was not significant which indicated that there was no specific change in the effect of the information content between the two periods. The estimated coefficients for the linear and quadratic terms of the time variable were statistically significant and of the expected sign for the "agreement" index. This suggests that there were increased perceptions and attitudes about calcium benefits over the two-year period, although this effect became less strong over time. Although the McFadden R~ values were low, the results show some ability to predict attitudes with socio- economic indicators. The significant model chi- square statistics indicate that the estimated model was statistically significant in being different from a model with an intercept alone.

Linking to the Consumption Data

The calcium advertisement tracking study described in the previous section collected information on dairy product consumption in terms of daily frequency of consumption per week Although this measure may be appropriate for identifying changes in the likelihood of consumption of new products, it is less appro- priate for explaining changes in consumption levels for items consumed more often during a day. Moreover, the empirical approach, de- scribed earlier, accounts for changes in like- lihood of purchases, and for increases in the actual level of consumption due to changes in attitude and awareness. The lack of good con- sumption data in the tracking survey led to the use of another survey conducted during the same period to provide more specific consumption information.

The 1985186 USDA "Continuing Survey of Food Intakes by Individuals" (CSFII), conducted from April 1985 through March 1986, collected data on consumption that overlapped with those of the period of the C A T survey (November 1985 through October 1987). For a description of the USDNCSFII survey and its methodology refer to USDA (1985). The CSFII data could be matched with that from the CAT survey for five months starting from November 1985 through March 1986. The sub- sequent analysis of consumption behavior was based on the five months of overlapping data from the CSFII 1985 in order to evaluate the effects of measured awareness on consumption patterns. Consumption patterns for women ages 19through 50 were evaluated by using observed daily calcium intake from dairy foods consumed directly (i.e., those used in mixtures o r ingredients in other food types were not included). Direct consumption of dairy products represents the major share of daily calcium intake and was the target of the advertising campaign.

For the five month period, the CSFII data contained 1,382 observations from 947 individu- als. For the purpose of this analysis, the panel nature of the survey was ignored. Since the data for individuals were collected at approximately

MEASURING THE IMPACT OF HEALTH AWARENESS Jensen, Kesavan, Johnson 305

Table 2. Indices of Attitudes, 1985-87

Description Mean S.D. Min. Max. Mode

Scored Modal Index SCIMP Scored Importance Index 4.34 1.81 0 7 5

SCAGR Scored Agreement Index 3.73 1.91 0 10 3

DSCIMP Modal Importance Index 0.67 0.47 0 1 1

DSCAGR Modal Agreement Index 0.87 0.36 0 1 1

DIMPAGR Importance Agreement Index 0.60 0.49 0 1 1

Table 3. Analysis of Attitude Indices: Estimated Logit Coefficients

Scored Index

ImportantIAgreement Important (DSCIMP) Agreement (DSCAGR) (DIMPAGR)

Asymptotic Asymptotic Asymptotic Coefficient 1-ratio Coefficient t-ratio Coefficient 1-ratio

Intercept

Income $15,000-24,999 25,000-39,999 40,000 and over Don't Know

Age 25-34 35 and over

High School

Full-Time Worker

Part-Time Worker

DUM8687 ..Denotes 5 percent level of significance.

O~enotes 10 percent level of significance.

Source: Market Facts, Inc., Calcium Ad Tracking (1985-87 (women 18-54)).

two month intervals, the observations could be deviations for the matched (five months) data treated as independent. In this case, ignoring set. the panel nature of the data still results in The CSFII survey and the advertisement consistent estimates (Robinson). Basically, each tracking survey were treated as two independent observation within the data was recognized as samples from the same population of women. if it came from a unique individual, with Distributions of sample characteristics are respective socioeconomic and demographic char- reported in Table 5. The null hypothesis that acteristics. Table 4 provides a description of the samples were drawn from the same popula- the variables with the means and standard tion of women was tested through chi-square

306 REVIEW OF AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

Table 4. Description of Variables: Continuing Survey of Food Intakes by Individuals

Standard Mean Deviation

Household Income ($)

Race Black (0,l) Other Nonwhite (0,l)

Full-Time Worker

Part-Time Worker

High School Grad (0,l)

Child Under 5 (0,l)

Meals at HometAway from Home

Region Northeasta Midwest South West

Location Central City Suburban Nonmetropolitana

Participation Rate Dairy Milk Cheese

Consumption (Calcium Equivalent) All Dairy Milk Cheese

aReference category.

Source: Continuing Survey of Food Intakes by Individuals 1985-86, USDA/HNIS (November 1985 to March 1986, unweighted data).

statistics. The sample proportions for the CSFII survey were found to be different from a pooled sample with respect to income, age, employment, and education but were not statistically different with regard to race. In the following analysis, no adjustment was made for these differences.

These characteristic variables entered the multi- variate analysis.

Estimation Issues

Equations (3) and (4) were applied to the CSFII data for dairy foods, milk, and cheese.

MEASURING THE IMPACT O F HEALTH AWARENESS Jensen, Kesavan, Johnson 307

Table 5. Comparison of Market Facts and CSFII Survey Data

Chi-Square Ad Tracking CSFII Test

Frequency Percentage Frequency Percentage Statistics

Income < $15,000 471 0.193 387 0.280 137.41' $15,000-24,999 540 0.221 358 0.259 x:, o.os=9.47 $25,000-39,499 623 0.255 377 0.273 > $40,000 453 0.185 25 1 0.182 Not Reported 353 0.145 9 0.007

Age 18-24 340 0.139 227 0.164 55.45' 25-34 624 0.256 526 0.381 X22 0 . 0 ~ 5 . 9 9

-> 35 1476 0.605 629 0.455

Race Black 231 ,095 129 0.093 0.12 Other Race 113 .046 61 0.044 ~t o.os=5.99 White 2096 .859 1192 0.863

Education Educated 1918 .786 1139 0.824 5.05' Not Educated 522 .214 243 0.176 2 0.05=3.84X I ,

Employment Other 91 1 ,373 769 0.556 76.27' Full-Time 1529 ,627 613 0.444 X : 005=3.86

'~ndicates chi-square test significant at 5 percent level when testing CSFII data against a pooled sample.

Sources: Market Facts. Inc.. Calcium Ad Tracking Survey, 1985-86, CSFll 1985-86. U S D M N I S .

Dairy food consumption includes all dairy variable assuming a value of 1 for those products including milk, cheese, and other dairy individuals with positive dairy product products. Separate equations were also estimated consumption, and zero otherwise. As stated for milk and cheese. Because no price informa- earlier, this equation was estimated using a tion was available, it was not included in the probit procedure. estimation. The latent attitude variable i was Because the demand for dairy foods was measured as the combined index of importance observed only for those individuals who con- and agreement, derived from estimated coeffi- sumed the dairy products, equation (4) was cients from the logistic function (equation 5). estimated accordingly. The dependent variables The estimated coefficients for the combined were the calcium equivalent of dairy, milk, and index of importance and agreement reported cheese products. T o correct for any sample in Table 3 were used as weights in constructing selection bias, an inverse Mills ratio was

the index for attitudes for each individual. included in the second stage (equation 4). The Accordingly, income, age, education, and time second stage involved estimating equation (4)

were used as predictors of the index. This based on the attitude, and the other explanatory

constructed index measured both types of attitudes: importance and agreement with 'The McFadden value for the importance index

health-related information. It performed at least was slightly greater than that for the importance/agreement index. Because the importancelagreement index measured

as well as did the other two separate m ~ a s u r e s . ~ two types of information, i t was preferred. The qualitative T o estimateequation (3), the dependent nature of the results was expected to be the same with either

variable was represented by a binary choice index variable.

308 REVIEW O F AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

variables, and the inverse Mills ratio (see Maddala).' Since the use of ge~era ted regressors such as the attitude index I in equation (4) (which is t distributed) could result in inconsistent standard errors (Pagan), the coefiicients and the standard errors for equation (4) were derived based on a bootstrapping procedure (see ~ f r o n ) . ~

Effect on Probability of Purchases

The probit results for the probability of purchases are presented in Table 6.The results indicate that the attitudevariable (importance and agreement index) had a statistically signifi- cant and positive effect on consumption of all dairy products and cheese. The attitude index did not, however, have a statistically significant effect for milk. Increased awareness and positive attitudes toward calcium made women more likely to consume dairy products and cheese, but not milk. This suggests that the increase in calcium information and more positive attitudes about calcium in dairy products led to increased likelihood of dairy consumers of a variety of dairy products, but not milk con- sumers. Further analysis of which other dairy products responded to the attitude index was not possible. Because milk is a dairy food with relatively established consumption patterns, this result is not all that surprising.

The results for the sociodemographic variables for the probability of dairy food consumption generally conform to prior expecta- tions. Age had a negative effect on probability consumption of cheese; being black had a

he inverse Mills ratio was computed based on equation (3), and defined as @(RB)A(RB) if q = l and @(Rb)I(((RB)-I) if q=O, where R is the set of exogenous variables included in estimating the probit model (Zi, Y, 91, is the vector of parameters, @ is the standard normal density function, and 4 is the cumulative normal density.

'?he bootstrap method invoked estimating equation (4) through ordinary least squares and resa_mpling CZI to generate a new set of dependent variables, qi=qi+e2,. By applying OLS with this new set of dependent variables, a different set of estimators was obtained. This process was repeated several times (500 replications in this study). The means of the estimators are reported as bootstrapped coefficients in Table 7.

negative effect on all dairy products and milk; and having children under five had a positive effect on dairy foods and milk. Those living in the South were less likely to consume dairy products and milk.

Effect on Conditional Demand of Dairy ,Products

The conditional demands for dairy pro- ducts were estimated based on the consumption and attitudes data, inverse Mills ratio and other socioeconomic factors. The estimated boot- strapped coefficients and standard errors based on 500 replications are reported in Table 7.

The results indicate that the attitude index was not statistically significant either for all dairy o r its products (milk o r cheese). This finding suggests that there was no increased dairy product consumption due to increased infor- mation about calcium among those who were already consuming the product.

Also, the inverse Mills ratio coefficients were not statistically significant factors determin- ing consumption for dairy products. This finding indicates that factors inducing the initial con- sumption decision were not important to the observed patterns of consumption through their impact on the likelihood ofconsuming the pro- duct at all. The ratio of meals consumed at home to those consumed away from home was statistically significant in explaining more dairy products and milk consumption. Dairy products, especially milk, a re consumed less away from home by women.

Among the socioeconomic factors, income and age had the expected effects on the dairy product consumption. Age had a negative effect, but income had a positive effect on dairy product consumption. Age also had a statistically significant negative effect on milk consumption. This is consistent with other recent studies (e.g., Haines et al.), and the fact that there was no control for whether or not the observed women were pregnant o r lactating (a condition more likely to affect the consumption patterns of the younger women). The results for location indicated that individuals in the Midwest Region consumed more dairy products than did those in the Northeast.

MEASURING T H E IMPACT OF HEALTH AWARENESS Jensen, Kesavan, Johnson 309

Table 6. Estimated Probit Coefficients for Consumption of Dairy Foods

All Dairy Milk Cheese Asymptotic Asymptotic Asymptotic

Coefficient t-ratio Coefficient t-ratio Coefficient t-ratio

Importance x Agreement Index

Income (10'~)

Age (10")

Race - Black

Children Under 5

Special Diet

Region Midwest South West

Central City

Suburban

Intercept

(-Log Likelihood)

x2(df)

McFadden R'

% of Correct Predictions

'Indicates significance at 10 percent level. ..Indicates significance at 5 percent level.

Source: CSFII 1985-86, USDA/HNIS (women 19-50, months November 1985 to March 1986).

Conclusions and Implications

This study analyzed the effects of consumers' attitudes and health awareness o n food consumption by utilizing attitude and food intake surveys. Scored attitude indices, con- structed from evidence in a calcium attitude study, were related to sociodemographic charac- teristics. The estimated parameters provided the basis for constructing a latent variable for health-related attitudes based on sociodemo- graphic variables as predictors. The same methodology could be applied in evaluations of health and nutrition information on consumption of other commodities, when the health and nutrition-related attitudes and awareness are not observed directly.

Because attitudes and health awareness are psychological variables that cannot be observed directly, the empirical specification relied on a latent variable model. Here the difficulties in constructing reliable and consistent measures of attitudes towards health and nutrient information posed a challenge. In this study, a set of indices reflecting consumer attitudes towards health and calcium were developed. The modal criteria imposed in index construction provided a starting point from which to develop more general indices. Better measures would have included more information on underlying distributional characteristics. This, however, would require a survey designed to obtain more than one observation per individual. The additional distribution information would

--

0.33

310 REVIEW O F AGRICULTURAL ECONOMICS, Vol. 14, No. 2, July 1992

Table 7. Estimated Bootstrapped Coefficients for Consumption of Dairy Foods

-

All Dairy Milk cheese Coefficient S. Error Coefficient S. Error Coefficient S. Error

Importance of Agreement Index 315.51 268.83 193.08 160.95 259.23 2364.90

Income (10.') 0.12" 0.05 -0.01 0.12 0.22

Age -6.59" 1.33 -6.39" 1.38 -2.85 28.76

Race Black -1 15.02 85.49 -239.33 224.12 -84.98 641.25 Other -74.69 39.68 -3 1.95 38.92 -81.58 61.57

Children Under 5 28.53 52.84 107.20 119.52 0.75 113.17

Special Diet -42.13 25.73 -24.18 30.47 -41.75 52.98 ..Meals at HomeIAway 3.35 1.04 2.57" 1.08 0.34 1.28

Region Midwest 59.20" 26.92 32.41 45.62 22.79 90.39 South -8.19 42.79 -1 14.83 182.07 20.91 53.53 West 60.13 40.67 19.38 63.97 1 1.29 41.23

Central City 91.13' 50.57 140.75 100.83 66.04 346.73

Suburban 32.94 29.65 80.41 62.56 -4.01 29.03

Inverse Mills Ratio 55.93 412.16 592.79 848.88 263.99 1865.80

Intercept 212.75 227.20 -49.99 458.10 -215.75 2657.00

R2 0.10 0.10 0.06

(-Log Likelihood) 8531.50 5993.30 3104.70

O~ndicates significance at 10 pcrcent level. ..Indicates significance at 5 pcrcent level.

Source: CSFII 1985-86, USDMINIS (women 19-50, months November 1985 to March 1986).

have been desirable in order to evaluate both milk with relatively ingrained consumption changes in the mean as well as variance of the patterns and attitudes toward the product. attitudes index. Increasingly, policy analysts, educators,

The empirical results based on dairy data and regulators are called upon to identify from the CSFII showed that positive attitudes linkages between nutrition-related advertise- towards calcium and health increased only the ments and information, and changes in behavior. likelihood of purchases of dairy products and Agricultural commodity group members have cheese. No statistically significant evidence, demanded accountability for expenditures of however, was observed for the effect of attitudes advertising dollars. The Federal Trade Commis- on the intensity (level) of consumption for any sion has evaluated the effect of promoting fiber dairy products. Promotion or nutrition education content in cereals. New federal legislation aimed at changingconsumers'attitudes toward directed at standardizing nutrition labeling is nutrition-related aspects of foods, and ultimately under review, an outgrowth of the concern that food consumption patterns, may be least effec- inaccurate o r misleading nutritional labels and tive a t altering demand for products such as claims about food products will lead consumers

MEASURING THE IMPACT OF HEALTH AWARENESS Jensen, Kesavan, Johnson 311

to make purchases they would not make if provided "better" (more truthful) information. For further analysis of the linkages between nutrition information and consumption behavior it is important not only to identify what can be done with existing data, but also to provide guidance on methods and the types of data needed to monitor such linkages in the future.

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Measuring the Impact of Health Awareness on Food DemandH. H. Jensen; T. Kesavan; S. R. JohnsonReview of Agricultural Economics, Vol. 14, No. 2. (Jul., 1992), pp. 299-312.Stable URL:

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References

Cholesterol Information and Shell Egg ConsumptionDeborah J. Brown; Lee F. SchraderAmerican Journal of Agricultural Economics, Vol. 72, No. 3. (Aug., 1990), pp. 548-555.Stable URL:

http://links.jstor.org/sici?sici=0002-9092%28199008%2972%3A3%3C548%3ACIASEC%3E2.0.CO%3B2-F

The Demand for Canadian Fats and Oils: A Case Study of Advertising EffectivenessEllen W. Goddard; Alex K. AmuahAmerican Journal of Agricultural Economics, Vol. 71, No. 3. (Aug., 1989), pp. 741-749.Stable URL:

http://links.jstor.org/sici?sici=0002-9092%28198908%2971%3A3%3C741%3ATDFCFA%3E2.0.CO%3B2-4

Modeling Food Consumption Decisions as a Two-Step ProcessPamela S. Haines; David K. Guilkey; Barry M. PopkinAmerican Journal of Agricultural Economics, Vol. 70, No. 3. (Aug., 1988), pp. 543-552.Stable URL:

http://links.jstor.org/sici?sici=0002-9092%28198808%2970%3A3%3C543%3AMFCDAA%3E2.0.CO%3B2-E

Econometric Issues in the Analysis of Regressions with Generated RegressorsAdrian PaganInternational Economic Review, Vol. 25, No. 1. (Feb., 1984), pp. 221-247.Stable URL:

http://links.jstor.org/sici?sici=0020-6598%28198402%2925%3A1%3C221%3AEIITAO%3E2.0.CO%3B2-9

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Food Consumption Changes of Adult Women between 1977 and 1985Barry M. Popkin; David K. Guilkey; Pamela S. HainesAmerican Journal of Agricultural Economics, Vol. 71, No. 4. (Nov., 1989), pp. 949-959.Stable URL:

http://links.jstor.org/sici?sici=0002-9092%28198911%2971%3A4%3C949%3AFCCOAW%3E2.0.CO%3B2-A

On the Asymptotic Properties of Estimators of Models Containing Limited DependentVariablesPeter M. RobinsonEconometrica, Vol. 50, No. 1. (Jan., 1982), pp. 27-41.Stable URL:

http://links.jstor.org/sici?sici=0012-9682%28198201%2950%3A1%3C27%3AOTAPOE%3E2.0.CO%3B2-T

Avoidance Costs Associated with Imperfect Information: The Case of KeponeDavid G. Swartz; Ivar E. Strand, Jr.Land Economics, Vol. 57, No. 2. (May, 1981), pp. 139-150.Stable URL:

http://links.jstor.org/sici?sici=0023-7639%28198105%2957%3A2%3C139%3AACAWII%3E2.0.CO%3B2-M

The Effects of Income, Assets, Food Programs, and Household Size on Food ConsumptionDonald A. West; David W. PriceAmerican Journal of Agricultural Economics, Vol. 58, No. 4, Part 1. (Nov., 1976), pp. 725-730.Stable URL:

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