Content-Type: text/html The Case of the Environment, 1987-1994 Unobtrusive Issues and the Agendas of the President, the Press, and the Public: The Case of the Environment, 1987-1994 Patrick M. Jablonski, Ph. D. Shannon Crosby Erica Bridges John Daniele Betsy Gray Lisa Mills The University of Central Florida School of Communication P.O. Box 161344 Orlando, Florida 32816-1344 (407) 823-9613 (Home) (407) 823-2840 (Office) [log in to unmask] A paper submitted to the Communication Theory and Methodology Division of the Association for Education in Journalism and Mass Communication Convention Meeting in Chicago, Illinois, 1997 The Case of the Environment, 1987-1994 Unobtrusive Issues and the Agendas of the President, the Press, and the Public: The Case of the Environment, 1987-1994 A paper submitted to the Communication Theory and Methodology Division of the Association for Education in Journalism and Mass Communication Convention Meeting in Chicago, Illinois, 1997 Abstract This study examines the relationship among the agendas of the mass media, the president, and the public regarding the issue of the environment in the United States from 1987 to 1994. ARIMA time-series analysis is used in an attempt to assess which factors drive the environmental issue agenda: the public, the press, or the president. Most important problem survey results from multiple organizations are aggregated into a series of 96 monthly time points to measure the public agenda. The media agenda is developed from a content analysis of the frequency of coverage of the environment issue in The New York Times. The presidential agenda is developed from a similar analysis of the Public Papers of the Presidents. The three univariate time series are identified, estimated, and diagnosed. The white-noise component of each series is subsequently employed in a bivariate cross-correlation analysis to address the research questions. Results indicate that the presidential agenda was significantly negatively correlated with the press agenda. No significant agenda setting relationship was detected involving the public. Unobtrusive Issues and the Agendas of the President, the Press, and the Public: The Case of the Environment, 1987-1994 Introduction Longitudinal agenda setting research in the past decade has focused on a variety of important public policy concerns, including the AIDS issue (Rogers, Dearing, & Chang, 1991), crime (Jablonski & Gonzenbach, 1997), drug abuse (Gonzenbach, 1992) and health care reform (Jablonski, 1996). These issues vary somewhat in the degree to which they impact the daily lives of the public. However, not all issues share such prominent places of concern in the public mind. Some issues do not rise and fall in the public opinion polls, but instead exist at the fringes of societal attention, rarely gaining national notice yet at the same time never entirely disappearing. An excellent example of this phenomenon is the environment issue in the United States. The purpose of this study is to investigate which factors were important in driving the environmental agenda in the United States from 1987 to 1994: the public, the president, or the press. Agenda Setting Research Agenda setting research traces much of its history to Walter Lippmann (1922), who was among the first to note that the issues which concern the public are in large part determined by the media. Years later, Cohen (1963) asserted that the media, while not successful in telling us what to think, were extremely successful in telling us what to think about. McCombs and Shaw's (1972) seminal study examining the relationship between the issue agenda of the public and the issue agenda of the press has spurred over a quarter century of research attention. According to the agenda setting hypothesis, the amount of public concern for an issue is in part a function of media emphasis of that issue. Agenda setting has developed in various forms since 1972. However, it is useful to classify agenda setting literature in terms of the fundamental aspects of causality that have been explicated by Babbie (1989) and others. Almost all agenda setting studies examine the correlation between the press and public opinion regarding important issues. The existence and effects of intervening variables have likewise been examined. However, investigations of the temporal relationship between the press and public opinion have taken years to evolve. The development of time order studies of agenda setting arose from the realization that agenda setting is a process. Specifically, the influence of the media on public opinion and vice-versa does not occur overnight. Cross-sectional studies by definition cannot examine such a process. Babbie (1989) notes that cross-sectional studies of processes are akin to taking a fast action photograph of a speeding car. The picture only tells the viewer what the car was doing at the moment the snapshot was taken. Studies which take into account the temporal relationship between two or more variables, moreover, give researchers a better idea as to how the process of agenda setting develops. In other words, operating within the original McCombs and Shaw model, a researcher would not be able to definitively indicate whether the press was responding to public opinion or vice versa. Longitudinal studies of agenda setting have flourished since the late 1980s. Kepplinger, Donsbach, Brosius, and Staab (1989) suggested that time series analysis can assist in investigating the question of whether the press drives or follows public opinion. Indeed, Watt and van den Berg (1978) provide the theoretical underpinnings of such an approach to the relationship between public opinion and the mass media. Kepplinger et al. (1989) rely on Watt and van den Berg (1978) in identifying and extending four theories about this relationship: 1) the mass media create public opinion, hence, the correlation between media content at one time will be more strongly correlated with public opinion at a later time than any other correlation; 2) the mass media mirror public opinion, meaning that the correlation between media and public agendas at the same time should be stronger than any other correlation; 3) public opinion creates media coverage, implying that the correlation between public opinion at one time will be more strongly correlated with public opinion at a later time than any other correlation; 4) there is no significant correlation between media coverage and public opinion. Gonzenbach (1992) applied these four theoretical approaches to the relationships among the president's public relations agenda, the media, and public opinion for the drug abuse issue. This study reported that there were significant bidirectional correlations among each of the linkages involving the president, the public, and the mass media. As far as the drug abuse issue was concerned, the president followed and drove the public agenda regarding drug abuse. The media mirrored, followed, and drove the drug abuse issue agenda of the president. Finally, the public mirrored, followed, and drove the drug abuse agenda of the media. This results in a triangular model of agenda setting, where the traditional agenda setting relationship between the press and the public is punctuated by the addition of a third variable. Figure 1 depicts just such an agenda setting model, where the life of an important issue in American political society develops not only from the relationship between the media and public opinion, but also from the relationships between these two variables and the president or other policy elite. The direction and strength of these relationships may vary with regard to the particular issue or setting. For instance, the public may set the media agenda, or vice-versa. Moreover, the public and the media may each contribute to the other's agenda. Finally, two of these variables might be correlated independent of the third variable. One would expect this situation with issues that annually exist on the national agenda, but lack the dynamism of major public policy matters. Figure 1. A Triangular Model of Agenda Setting [--- Pict Graphic Goes Here ---] In a similar approach, Rogers, Dearing, and Chang (1991) utilized Granger causality tests and multivariate correlations within an Autoregressive Integrated Moving Averages (ARIMA) framework to investigate the inter-relationships of real-world cues, the science agenda, the media agenda, the polling agenda, and the policy agenda for the public issue of AIDS. ARIMA allows the researcher to identify and statistically control for the presence of autoregressive terms in the model. The inclusion of agendas other than the media indicates that the life of an issue may be influenced by a number of factors in addition to the media and the public. Public Opinion and the Mass Media There are indications that the media-public relationship is not unidirectional (Ansolabehere, Behr, & Iyengar, 1993). A myriad of studies and reviews examine this linkage. Many agenda setting studies generally conclude that the mass media impact public opinion and vice-versa. In the years following McCombs and Shaw's (1972) study, several researchers examined the effect of the media on political opinions and attitudes. Weaver et al. (1981) found that the mass media contribute to public evaluations of political candidates, and not just images. The media additionally influence public opinion by choosing to ignore certain issues. Breed (1958) was among the first to demonstrate that media decisions in the newsroom affect what issues become important. Page and Shapiro (1992) also claim that public opinion about unemployment and other issues shifted in relationship to the tone of media coverage. Specific to the environmental issue, Hester and Gonzenbach (1994) and Ader (1995) reported a significant relationship between the media and the public. However, the Ader study did not model the data to avoid problems with autoregression, possibly resulting in flawed testing of hypotheses. Neither study examined the effects of political elites on the agenda setting relationship. The relationship between the mass media and public opinion is not always unidirectional. Fan and Norem (1992) argue that assessments of the public sentiment by the press and public opinion polls may direct press coverage of important issues. Rogers and Dearing (1988) contend that there is a "two-way mutually dependent relationship between the public agenda and the media agenda" (p. 571). The public may direct and focus media coverage, which in turn may affect public opinion. Conversely, mass media coverage might drive public opinion, which in turn affects subsequent coverage. This phenomenon is demonstrated by the findings of Kepplinger et al. (1989). They report that press coverage about German Chancellor Helmut Kohl preceded public opinion. Most important, media coverage also followed public opinion, albeit with a different tone. The President and Public Opinion Public opinion is not solely affected by the mass media. Political elites, interest groups and major organizations may also affect the public agenda (Shaw & McCombs, 1989). Graber (1982), Behr and Iyengar (1985) and others acknowledge that the president is the most prominent American political figure and receives the plurality of media and public attention. Similar to the interaction of the press and public opinion the president likewise affects and is affected by the press and public opinion. Converse (1987) claims that public opinion affects the president and policy-making. The opposite effect can be true as well. The president can alter the public agenda by advocating certain legislative or moral positions in oral, written, and symbolic communications (Chapel, 1976). As the focal point of American politics (Denton & Hahn, 1986), the president has been granted powers that make it possible to set the public agenda (Waterman, 1989). While Converse (1987) and others claim that public opinion affects the president and policy-making, the opposite effect may be simultaneously observed. Page and Shapiro (1992) conclude, "Part of the estimated impact of popular presidents probably reflects a reciprocal relationship, in which popularity-seeking presidents take a stand in response to public opinion or in anticipation of it" (p. 349). Page and Petracca (1983) likewise suggest that the linkage between the president and public opinion is reciprocal. Ansolabehere, Behr, and Iyengar (1993) note that the television era has elevated the importance of mobilizing public opinion in support of the president. The president uses a myriad of persuasive tools (Graber, 1982), including, but not limited to, public statements, press conferences, and proclamations (Zernicke, 1990; Shull, 1983) which are aimed at the whole country, not just the immediate audience (Ansolabehere, Behr, & Iyengar, 1993). Moreover, the president's importance, by the very nature of his or her responsibilities, provides an opportunity to regularly communicate a specific agenda (Behr & Iyengar, 1985) which has a significant effect on public opinion (Gilbert, 1981). As Miroff (1976) concludes, "Public awareness of issues is largely governed by the problems the president has defined and the battles he is engaged in fighting. His role in the public space is so prominent that it is sometimes hard for others simply to be seen on any large scale" (pp. 99-100). Further, the White House also pays close attention to public opinion polls communicated by the media (Bogart, 1985; Bradburn & Sudman, 1988; Hinckley, 1990; Spragens, 1979). Modern presidents regularly retain personal pollsters in order to stay in touch with the electorate, and not just with interest groups (Graber, 1982). The public therefore may communicate with the president indirectly, through answers to public opinion polls. Media use of public opinion polls is also increasing (Delli Carpini & Keeter, 1992), perhaps solidifying the role of the media as an emissary between the public and the president. The President and the Mass Media Similar to the previous relationships, the media and the president may influence each other over time (Denton & Hahn, 1986). Put simply, the media can influence the presidential agenda while the president can influence the media agenda. The media provide the president with exposure to the public and vice versa (Graber, 1982; Edwards & Wayne, 1985). In addition, the press covers everything a president does, adding to the considerable amount of news coverage devoted to the White House (Orman, 1990). This also enlarges the typical audience for any one presidential message (Denton & Hahn, 1986). More important, a president may transmit a list of priorities to the public and Congress at the start of an administration through the mass media (Light, 1991). This is an important ability, especially if the role of the president is to shape national attitudes into a coherent policy (Powell, 1986). Another major characteristic of the press-president relationship is that the president provides news stories. The president may therefore play a major role in agenda-building, or influencing the news media agenda (Gilberg et al., 1980; Lang & Lang, 1981; Weaver & Elliott, 1985; Turk, 1986; Robinson, 1990). Levels of press coverage are very often affected by the president's explicated agenda. Presidents can create news by holding press conferences and photo opportunities, among other ceremonies (Ansolabehere, Behr, & Iyengar, 1993). Presidents use pseudo-events and other communication opportunities to influence news coverage (Denton & Hahn, 1986, p. 275). Indeed, Behr and Iyengar (1985) found that a single presidential speech on a given issue can result in as many as ten stories. The agenda-building process can work in the other direction as well. Cobb and Elder (1972) posit that the mass media play a huge role in elevating issues to the presidential agenda. Therefore, the mass media can directly affect the presidential agenda. Schmid (1992) demonstrates that the president can be directly affected by mass media coverage of terrorism. Indeed, terrorism was elevated to the presidential agenda in the early 1980s after high degrees of press coverage. Weaver's (1990) attempt to define the direction of influence in the press-politician relationship concludes that the linkage's characteristics are largely case-specific. In some situations, the press have the upper hand, while in other situations, the politicians drive the agenda Issue Obtrusiveness Another major aspect of agenda setting research focuses on issue obtrusiveness. Obtrusiveness is defined as the amount of personal experience people can have with an issue (Demers et al., 1989). The importance of obtrusiveness in media effects is rather obvious. For example, people directly affected by crime do not need media coverage to tell them that crime is important. Typically, theory indicates that for less obtrusive issues the potential for agenda setting increases. Two models have evolved from research surrounding issue obtrusiveness and agenda setting. They are, the obtrusive contingency, which holds that agenda setting effects decrease as the obtrusiveness of, or amount of personal experience with, an issue increases; and the cognitive-priming contingency, which posits just the opposite--that agenda setting effects increase as obtrusiveness increases (Demers et al., 1989). The environment is not an obtrusive issue as the public has little direct experience with it (Zucker, 1978; Eyal, Winter, & DeGeorge, 1981; Behr & Iyengar, 1985; Hester & Gonzenbach, 1994; Ader, 1995). Hence, one would expect that the issue could be very much driven by the mass media. Consequently, the environment has been the subject of a number of agenda setting studies. Hester and Gonzenbach (1994) found a significant agenda setting relationship between the electronic media and the public regarding the environment which occurred independent of real world cues (Behr & Iyengar, 1985). Ader (1995) reported a similar relationship between the coverage of The New York Times, real world cues, and the public agenda regarding the environment. Atwater, Salwen, and Anderson (1985) found a basic agenda setting effect as did Brosius and Kepplinger (1990). Finally, Protess et al. (1987) did not find an agenda setting effect on public opinion in their examination of an investigative report about toxic waste in Chicago. However, they did detect media influence on political elites in the area. The role of higher level political elites in environmental agenda setting has not received much research attention. Research Questions This work draws most specifically upon the time series investigations of agenda setting by Gonzenbach (1992), Rogers et al. (1991) and Kepplinger et al. (1989). This study seeks to address 3 basic questions about the roles played by the press, the president, and public opinion with regard to the environment: RQ1) Do the mass media create public opinion or does public opinion determine the media's agenda? RQ2) Does the president's agenda create the media agenda or does the media agenda set the president's agenda? RQ3) Does the president create public opinion, or does public opinion create the president's agenda? Method Data Public opinion. This study combines multiple, similarly worded "most important problem" survey questions from 13 different public opinion organizations in order to measure the public agenda. The percentages of environment being mentioned as the most important problem were tracked from January 1987 until December 1994. The mass media. This study utilizes a content analysis of the media environment agenda in The New York Times. The New York Times was used because it is the elite newspaper in the United States and is fairly robust to the proximity effects of major issues (Winter & Eyal, 1981). The unit of analysis was individual articles about the environment. The Lexis/Nexis-based New York Times listing was used. The search string which was utilized was, " Environment or endangered species or global warming or ozone layer or toxic waste or air pollution or water pollution or recycling and date aft December 1986 and date bef January 1995." Only articles in the national news and editorial sections of the New York Times were recorded. Articles from the Connecticut Weekly Desk, the Long Island Weekly Desk, the Magazine Desk, the Metropolitan Desk, and the Financial Desk were excluded because those items may reflect only regional or local interest. Letters to the editor and book reviews were also excluded. In addition, to avoid duplication of articles, news summary pieces were excluded from the analysis since they merely summarize articles already in that day's newspaper. Each story was content analyzed to ascertain the article's relationship to the environment issue. Finally, the monthly frequency of environment articles was used primarily because this method was more efficient in terms of time and money than calculating column inches or minutes of coverage. The use of frequency counts has been found to be a fairly reliable measure of media content, and is comparable to the tabulation of column inches (Stone & McCombs, 1981). The president. Similarly, the presidential agenda is measured via the public relations efforts of the presidents. The Public Papers of the Presidents was utilized to determine the monthly frequency of mentions of the environment issue by the sitting president. This resource is also included in the Nexis library. The search string utilized was, "Environment and date aft December 1986 and date bef January 1995." The retrieved documents were analyzed for their relevance to the research topic. Statistical Analysis This investigation utilizes Autoregressive Integrated Moving Averages (ARIMA) time series analysis as popularized by Box and Jenkins (1976). ARIMA is an excellent time series analytical tool since it calculates the first- and second-order autoregression within each series. In other words, for a given series, the error terms or residuals at different points in time should not be correlated. When this occurs, the estimated regression model fits the data very well, since the model underestimates the true variability of the residuals. The result may be a deceptively inaccurate model, which in turn leads to inaccurate testing of hypotheses. ARIMA analysis is used to determine and model the errors which may make a time series largely unpredictable. In effect, the ARIMA procedure increases the accuracy of the forecast model, resulting in more accurate hypothesis testing. ARIMA analysis typically models three processes: autoregression (AR), differencing to eliminate the integration (I) of the series, and moving averages (MA). All three are based on Box and Jenkins' (1976) concept of random disturbances or shocks. Between two observations in a series, a disturbance or shock occurs that may alter the series. These disturbances can be modeled using ARIMA techniques within such software packages as SPSS or SAS. "The most general ARIMA model involves all three processes. Each is described by a small integer. The general model, neglecting seasonality, is traditionally written ARIMA (p, d, q ), where p is the order of autoregression, d is the degree of differencing, and q is the order of moving average involved" (SPSS, Inc., 1988, p. B-31). The ARIMA procedure requires the researcher to construct the best model for any given series. Box and Jenkins (1976) conceptualized three steps in this process: identification, estimation, and diagnosis, which is repeated until the model is satisfactory. Identification is the most subjective step in the analysis. The researcher must determine the p, d, q integers in the ARIMA process governing the series using a plot of the data. Once the p, d, q integers are determined, the ARIMA procedure estimates the coefficients of the given model. ARIMA modeling additionally allows the researcher to examine the relationship between two series. In fact, this is an easy step which only requires the researcher to input the series to be analyzed. The output is a cross-correlation analysis, which compares the two series to determine if the series are correlated at any points in time. In other words, the independent series at month k is compared to the dependent series at all months so that the different correlations can be calculated appropriately. The correlations are calculated in this manner for all months of both series. In the present study, ARIMA modeling is used to identify, estimate, and diagnose each of the three univariate time series. Cross-lagged correlations were then calculated for all bivariate permutations of the three variables: the press, public, and the president (McCleary & Hay, 1980). Six-month lags were calculated in each direction for the cross-lagged correlations. While Winter and Eyal (1981) determined that a four to six week span is optimal, Stone and McCombs (1981) found that the process of adapting media changes in the public agenda may take between two and six months. Shoemaker et al. (1989) reported that the optimal effects were several weeks and three months preceding a poll. Meanwhile, Kepplinger et al. (1989) found optimal effects three months prior to the poll. In other words, support was found for the immediate agenda-setting effects of the media as reported by Shoemaker et al. (1989) and Erbring et al., (1980) in addition to the long-term (6-month) correlations found by Kepplinger et al. (1989) and Brosius and Kepplinger (1990). Hence, the media affect public opinion and vice-versa, though to different degrees and perhaps at different points in time. Results Frequency Analysis The data indicate that the environment issue variously rose and fell in prominence in each of the agenda measures from 1987 until the end of 1994. The scale of importance accorded the issue, however, is lower than that observed for other major national issues such as crime, AIDS, health care, or drug abuse. Figure 2 represents the agendas for each variable from January 1987 until December 1994. Public opinion. The environment does not appear to be viewed as the most important problem by very many Americans between 1987 and 1994. This may be a result of the unobtrusive nature of the issue. Other issues may impact the public more directly or more forcefully, pushing the environment away from the upper half of the public agenda, but not off the agenda entirely. A key event in the life of the issue was the Exxon Valdez disaster in March 1989. Subsequent public opinion polls indicated that the environmental issue was fairly important, with 10.5% of the mentions as the country's most important problem by the end of March, 1989. However, the issue dropped in importance rather precipitously by the end of 1989. The issue more or less declined in significance until 1995. The New York Times. Coverage in The New York Times appears nearly cyclical in nature, with occasional increases in the number of articles about the environment throughout the time period of this study. Interestingly, the results of the content analysis portion of this study do not match those reported by Hester and Gonzenbach's (1994) analysis of the environmental issue. Their investigation utilized television news as the media measure. The difference may explain why the Valdez disaster does not result in much influence on the media measure utilized here. Perhaps the first major wave of print media coverage did not tie the oil spill to the environmental issue. This would make some degree of sense, given Hester and Gonzenbach's (1994) assertion that the environmental issue is an electronic media phenomenon and lends itself to compelling video images. The print media are not able to rely on visual images, and instead must base their coverage in larger part on the importance of the events themselves. Presidential Agenda. Presidential attention to the environment issue, as measured by the Public Papers of the Presidents, remains stable and low throughout the time period of this study, except for at the end of 1991. Attention to the issue increases after the Valdez disaster and other environmentally-oriented events unfold, such as the impact of the Gulf War fires and oil spills in 1991. Interestingly, it appears as if the president and The New York Times have an inverse relationship at a number of points in time. Increases in environmental coverage appear to be followed by presidential inattention. Subsequently, periods of heightened presidential attention appear to spur media inattention. ARIMA Modeling Univariate series analysis. The nature of the three time series was explicated with the ARIMA analysis. Table 1 demonstrates the ARIMA model terms for each series, along with the estimates of how well each model fits the corresponding data. Table 1 ARIMA Analysis of Univariate Series Series ARIMA term Coefficients t ratio p Public Opinion (0,1,0) New York Times (1,0,0) f1 = .30 3.00 .003 President (1,0,0) f1 = .41 4.29 .000 The ARIMA model for the univariate public opinion series indicated a differenced, first-order moving average process: (0,1,0). The ARIMA models for the presidential time series and The New York Times indicated strong first-order autoregressive processes: (1,0,0). ARIMA cross-correlation analysis. Once the ARIMA model for each univariate series is determined, the bivariate relationships among the variables can be studied. The bivariate analysis takes each modeled series and examines the cross-lagged correlations for each possible paired combination (Gonzenbach, 1992; Vandaele, 1983). The cross-lagged correlation process treats one of the series as dependent and the other as independent. The analysis examines the relationship between the independent series at a given month k and the dependent series for each of the 12 months prior to k and after the month k, which becomes known as the synchronous or mirrored relationship. Hence, the relationship between, say, public opinion (the dependent series) at month k and the president (the independent series) at a prior month, k-4, is referred to as the relationship of the president at lag -4 upon public opinion (Gonzenbach, 1992). Cross-correlation analysis of the pre-whitened, univariate series reveals the correlations among the media, the public, and the president. As Table 2 indicates, there are only two significant relationships detected for all of the cross-lagged correlations for the three variables. Discussion This investigation indicates that newspaper coverage of the environment in the United States from 1987 to 1994 does not have an agenda setting effect upon the public. There is similarly no relationship on the press from the public. Further, the environmental agendas of the public and the president likewise have no significant relationship over time. The only significant correlations resulting from the analysis in this study occur between the press and the president. However, the correlations are negative. This means that the president tends to behave directly opposite from the coverage of the New York Times at a lag of +2. Hence, increased coverage of the environment in January is correlated with decreased presidential attention to the environment in March. The research questions forwarded earlier can all be answered negatively in fairly definitive fashion, given the lack of significant findings from the cross correlation analysis. The results reported here do not support the significant agenda setting relationship reported by Ader (1995). Perhaps the difference between the two investigations lies in the fact that the present study utilized ARIMA time series modeling to guard against autoregression. Once the data were modeled, no agenda setting or agenda building relationship could be detected. In addition, this study provides a compelling contrast to the results of the Hester and Gonzenbach (1994) analysis of the environment and television news coverage. The results here may on their face appear to fail to support their conclusions. However, the fact that the print media appear to lack a significant agenda setting relationship with the public may confirm the finding that the environmental issue is driven by quickly-moving visual events (Hester & Gonzenbach, 1994). This study also fails to detect a significant agenda building relationship between the president and the media. The media seem to take their cues on the environmental issue from events, not the moves of the president nor the mood of the public. Real world cues, as operationalized in other studies, are not necessarily event-oriented and may not provide a very good explanation for media behavior regarding the environment. The addition of the president to this investigation serves as a differential replication for prior research which only examined the relationships among the press, the public, and real world cues. Perhaps the results reported here should not be surprising. The environment is important to many Americans, but rarely rises high enough on the public agenda to gain (or warrant) sustained notice by the media and by politicians. The media in turn may have their own environmental agenda independent of the president and the public. Of much more importance are the implications of the findings reported here for the conceptualization of obtrusive issues. Perhaps issues can be so unobtrusive that they fall quite low on the agendas of the public and the president. One cannot detect an agenda setting effect if there is no agenda to be set. The environment seems to fit this type of issue. The public has so little direct experience with the issue that they rely on media accounts of events for information. However, since there is little contact with the issue, only subsequent media accounts of later events can sustain interest in the environment. Once those events fade from the front page, the issue fades as well. In this view, the media may keep relating stories about the environment, but the public and the president are paying attention to other issues and events. One major shortcoming to this study is that it draws bivariate comparisons among the series, not multivariate comparisons. The simultaneous effects of third variables cannot be determined and controlled (Fan, 1988). This study provides a picture of the agenda relationships regarding the environment, but it does not provide a description of the existence of intervening variables or the interaction effects of multiple agendas. Future research should utilize multivariate analysis to ascertain if there are any interaction effects among the agendas included in this analysis. In other words, a multivariate analysis would enable the researcher to draw better conclusions about the existence and impact of intervening variables. In addition, such an analysis would indicate the relative strengths of the individual relationships depicted in the present study. This would enable determinations about which agendas exert the most influence on the other agendas at specific points in time. Future research should combine the media agenda as operationalized here with the electronic media agenda developed by Hester and Gonzenbach (1994). Perhaps this aggregate measure would be a more representative variable than merely using the print media and electronic media separately. In addition, future research should strive to develop better real world indicators of the environment. The issue is so unobtrusive that measures used in previous research do not appear to have any kind of possible impact on the public, such as the amount of toxic chemicals released into the environment. Future researchers should also strive toward assimilating the growing body of agenda setting research on individual issues. Perhaps a taxonomy of obtrusiveness can be developed from such an effort. A more important project for future research would be to aggregate the findings of longitudinal studies of single issues which utilize similar methods. The resulting multiple issue time series model might give researchers a much better picture of why issues fall off of agendas. The single issue model as used here does not take into account the influence of issues such as health care on the environmental issue as they (and other issues) fight for the finite agenda space of the press, the president, and the public. This approach could give agenda setting theory a new stage in development by relating the original cross sectional multiple issue studies of years ago back to the longitudinal studies of today. References Ader, C. (1995). A longitudinal study of agenda setting for the issue of environmental pollution. Journalism and Mass Communication Quarterly, 72, 300-311. Ansolabehere, S., Behr, R., & Iyengar, S. (1993). The media game: American politics in the television age. New York: Macmillan. Atwater, T., Salwen, M. B., & Anderson, R. B. (1985). Media agenda setting with environmental issues. Journalism Quarterly, 62, 393-397. Babbie, E. R. (1989). The practice of social research. Belmont, CA: Wadsworth. Behr, R. L. & Iyengar, S. (1985). 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