多 FIGURE 1.Changes in Average Marginal State Income Tax Rate,Public Welfare Spending Per Capita,and Percent Foreign-born Population: 2004to1990 Attitudes toward Immigration CT Loess Fit Reg.Fit 虽 DC Loess Fit Reg.Fit AK NM ME MS M 金 DE MA U KY KS NE LA MO NE一 OR NC -DC NM VA CA OK SD ND AZ MT ND ALA CT GA SD NAK N锅 CO MT A M NY co DE H Y 业L LLLILLLL1L⊥ 业LLLL⊥L⊥ 0 2 6 10 0 2 4 6 8 10 Change in Percent Foreign Born:2004 to 1990 Change in Percent Foreign Born:2004 to 1990 February 2010
Attitudes toward Immigration February 2010 FIGURE 1. Changes in Average Marginal State Income Tax Rate, Public Welfare Spending Per Capita, and Percent Foreign-born Population: 2004 to 1990 0 2 4 6 8 10 –2 0 2 4 Change in Percent Foreign Born: 2004 to 1990 Change in Avg. Marginal State Income Tax Rate: 2004 to 1990 MTWVME MSSDVTLANDOHNHWYALKYIAMOAKPAWI INKSMI OKSCARTNRIIDCTNEDCMNUTHI NMMEAN MADEORMDVAWANCILFLCANYCOGA TXNJ AZ NV Loess Fit Reg. Fit 0 2 4 6 8 10 0 500 1000 1500 Change in Percent Foreign Born: 2004 to 1990 Change in Public Welfare Expenditure per capita: 2004 to 1990 MTWVME MSSDVTLANDOHNHWYALKYMOIAAKPAWI INKSMI OKSCARTNRIIDCTNEDCMNUTHI NMMEAN MADEORMDVAWANCILFLCANYCOGA TXNJ AZ NV Loess Fit Reg. Fit 66
American Political Science Review Vol.104,No.1 propositions.No study to date has been able to Version 1:Do you agree or disagree that the US distinguish between attitudes toward highly skilled should allow more highly skilled immi- immigrants and attitudes toward low-skilled immi- grants from other countries to come and grants,even though this distinction is a critical fea- live here?(emphasis added) ture of the theoretical story.Below we describe a Version 2:Do you agree or disagree that the US survey experiment aimed at addressing this short- should allow more low-skilled immi- coming and providing an explicit test of arguments grants from other countries to come and about how economic concerns shape attitudes toward live here?(emphasis added) immigration. Answer options (both versions): THE SURVEY EXPERIMENT Strongly Somewhat Neither agree disagree disagree nor disagree Design 2 3 Our experiment was embedded in the Cognitive Styles Somewhat Strongly Survey (CSS),a survey instrument designed to study agree agree opinions regarding trade and immigration.The CSS was administered by the research firm Knowledge The two question versions differed only in that they Networks (KN)and fielded between December described the immigrants'skill level as either highly 2007 and January 2008 to some 2.285 panelists who skilled or low-skilled.15 Accordingly,for half the re- were randomly drawn from the KN panel.Of these. spondents,referred to as the treatment group,we 1,601 responded to the invitation,yielding a final measured preferences over highly skilled immigration, stage completion rate of 70.1%.11 The KN panel is whereas for the other half,referred to as the control a probability-based panel where all members have group,we measured preferences over low-skilled immi- a known probability of selection.It covers both the gration.Randomization ensured that the two groups of online and offline U.S.populations aged 18 years respondents were (in expectation)identical in all other and older.The sampling procedure for the CSS thus observed and unobserved characteristics that may con- constitutes a two-stage probability design.12 The found a comparison across groups.16 recruitment rate for this study,reported by KN using The general distribution of preferences over both the AAPOR Response Rate 3(RR3)guidelines,was highly skilled and low-skilled immigrants is displayed 24.6%.13 The final respondent data were adjusted for in Figure 2.For both types of immigration the barplots the common sources of survey error (nonresponse, show the fraction of respondents answering each of coverage error,etc.)using poststratification weights.14 the five answer categories;the superimposed whiskers The rate of item nonresponse was very low,below 1% decode the upper.95 confidence interval derived from for the questions we use in the analysis below. the design-based variance estimator.Two features For the core experiment,we randomly allocated re- stand out in this graph.First,in line with previous spondents to two groups of equal size and presented studies,our survey once again confirms the profound each group with one of two versions of the survey ques- divide among the American public in opinions on tion about immigration: immigration.Pooling over both types of immigration, about 50%of the respondents oppose an increase in immigration,whereas about 25%favor it.Second and 11 All fielded sample cases had one e-mail reminder sent three days more importantly,our findings for the first time docu- ment the fact that preferences over immigration vary after the initial email invitation.No monetary incentive was used in the CSS study.Of the invited respondents,4.5%did break off before rather dramatically depending on the immigrants'skill the interview was completed. levels.Although more than 60%of the respondents 12 Panel members are randomly selected using random digit dialing (in the control group)state that they strongly disagree (RDD)sampling techniques on the sample frame consisting of the or somewhat disagree with an increase in low-skilled entire U.S.residential telephone population (both listed and un- immigration,only 40%of the respondents (in the listed phone numbers).Households are provided with access to the Internet and hardware if needed.In contrast to opt-in Web panels, treatment group)are opposed to an increase in highly unselected volunteers are not allowed to join the KN panel.A de- skilled immigration.7 Because of the randomization, tailed report about the KN recruitment methodology and the survey f panle 15 Notice that we stratified the random assignment by four education recruited at different times and committed to answer several surveys levels(described below)so that an equal number of respondents for a period of time.KN panelists must also complete profiling sur- within each education level received the two different versions of veys in order to become members of the panel.These differences the question. make directly comparing response rates between one-time surveys 16 We conducted extensive balance checks by comparing the distri- (such as simple RDD telephone or mail sample)and panel surveys butions of all our covariates in both groups.All tests confirmed that difficult and perhaps not illuminating.See Callegaro and DiSogra (as expected given the large sample size)randomization balanced (2008)for an extended description of how to compute response the distributions evenly.Results are available upon request. metrics for online panels. 14 Poststratification weights are raked to adjust to the demographic 17 In the preimplementation pilot testing.we created a third. "vanilla"version of the question that referred simply to "im- and geographic distributions from the March Supplement of the 2007 migrants",without mentioning skill levels,and we randomly as- Current Population Survey. signed respondents into a third group who answered this question 67
American Political Science Review Vol. 104, No. 1 propositions. No study to date has been able to distinguish between attitudes toward highly skilled immigrants and attitudes toward low-skilled immigrants, even though this distinction is a critical feature of the theoretical story. Below we describe a survey experiment aimed at addressing this shortcoming and providing an explicit test of arguments about how economic concerns shape attitudes toward immigration. THE SURVEY EXPERIMENT Design Our experiment was embedded in the Cognitive Styles Survey (CSS), a survey instrument designed to study opinions regarding trade and immigration. The CSS was administered by the research firm Knowledge Networks (KN) and fielded between December 2007 and January 2008 to some 2,285 panelists who were randomly drawn from the KN panel. Of these, 1,601 responded to the invitation, yielding a final stage completion rate of 70.1 %.11 The KN panel is a probability-based panel where all members have a known probability of selection. It covers both the online and offline U.S. populations aged 18 years and older. The sampling procedure for the CSS thus constitutes a two-stage probability design.12 The recruitment rate for this study, reported by KN using the AAPOR Response Rate 3 (RR3) guidelines, was 24.6%.13 The final respondent data were adjusted for the common sources of survey error (nonresponse, coverage error, etc.) using poststratification weights.14 The rate of item nonresponse was very low, below 1% for the questions we use in the analysis below. For the core experiment, we randomly allocated respondents to two groups of equal size and presented each group with one of two versions of the survey question about immigration: 11 All fielded sample cases had one e-mail reminder sent three days after the initial email invitation. No monetary incentive was used in the CSS study. Of the invited respondents, 4.5 % did break off before the interview was completed. 12 Panel members are randomly selected using random digit dialing (RDD) sampling techniques on the sample frame consisting of the entire U.S. residential telephone population (both listed and unlisted phone numbers). Households are provided with access to the Internet and hardware if needed. In contrast to opt-in Web panels, unselected volunteers are not allowed to join the KN panel. A detailed report about the KN recruitment methodology and the survey administration is available from the authors upon request. 13 Notice that an online panel such as KN is composed of people recruited at different times and committed to answer several surveys for a period of time. KN panelists must also complete profiling surveys in order to become members of the panel. These differences make directly comparing response rates between one-time surveys (such as simple RDD telephone or mail sample) and panel surveys difficult and perhaps not illuminating. See Callegaro and DiSogra (2008) for an extended description of how to compute response metrics for online panels. 14 Poststratification weights are raked to adjust to the demographic and geographic distributions from the March Supplement of the 2007 Current Population Survey. Version 1: Do you agree or disagree that the US should allow more highly skilled immigrants from other countries to come and live here? (emphasis added) Version 2: Do you agree or disagree that the US should allow more low-skilled immigrants from other countries to come and live here? (emphasis added) Answer options (both versions): Strongly Somewhat Neither agree disagree disagree nor disagree 12 3 Somewhat Strongly agree agree 4 5 The two question versions differed only in that they described the immigrants’ skill level as either highly skilled or low-skilled. 15 Accordingly, for half the respondents, referred to as the treatment group, we measured preferences over highly skilled immigration, whereas for the other half, referred to as the control group, we measured preferences over low-skilled immigration. Randomization ensured that the two groups of respondents were (in expectation) identical in all other observed and unobserved characteristics that may confound a comparison across groups.16 The general distribution of preferences over both highly skilled and low-skilled immigrants is displayed in Figure 2. For both types of immigration the barplots show the fraction of respondents answering each of the five answer categories; the superimposed whiskers decode the upper .95 confidence interval derived from the design-based variance estimator. Two features stand out in this graph. First, in line with previous studies, our survey once again confirms the profound divide among the American public in opinions on immigration. Pooling over both types of immigration, about 50% of the respondents oppose an increase in immigration, whereas about 25% favor it. Second and more importantly, our findings for the first time document the fact that preferences over immigration vary rather dramatically depending on the immigrants’ skill levels. Although more than 60% of the respondents (in the control group) state that they strongly disagree or somewhat disagree with an increase in low-skilled immigration, only 40% of the respondents (in the treatment group) are opposed to an increase in highly skilled immigration.17 Because of the randomization, 15 Notice that we stratified the random assignment by four education levels (described below) so that an equal number of respondents within each education level received the two different versions of the question. 16 We conducted extensive balance checks by comparing the distributions of all our covariates in both groups. All tests confirmed that (as expected given the large sample size) randomization balanced the distributions evenly. Results are available upon request. 17 In the preimplementation pilot testing, we created a third, “vanilla” version of the question that referred simply to “immigrants”, without mentioning skill levels, and we randomly assigned respondents into a third group who answered this question. 67
Attitudes toward Immigration February 2010 EMPIRICAL TEST I:THE LABOR MARKET FIGURE 2. Support for Highly Skilled and COMPETITION MODEL Low-skilled Immigration ◆ Skill Levels of Natives Strongly agree Agee r agree nor disagree If concerns about labor market competition are im- disagree portant in shaping attitudes toward immigration,we Upper 95%confidence bound expect,in line with the FP model of attitude formation, that natives should oppose immigrants with similar skill levels but favor immigrants with different skill levels. That is,we expect that the skill levels of our survey re- spondents should have a large and positive relationship with support for low-skilled immigrants and a large and negative effect on support for highly skilled immigrants. To conduct an explicit test of this argument,we follow previous studies and employ educational at- tainment as our measure of respondent skill levels (Facchini and Mayda 2009:Hanson.Scheve.and Slaughter 2007,2008;Mayda and Rodrik 2005;Scheve and Slaughter 2001).This measure,which we label 0.1 0.2 0.3 EDUCATION.is a categorical indicator of the highest 0.4 0.5 0.6 Fraction level of education attained by the respondent.The cod- ing is:1 Not completed high school education,2= High school graduate,3 =Some college,4 Bache- lor's degree or higher.Alternatively,we also use a set we know that this statistically significant difference of binary indicator variables called HS DROPOUT, between the two distributions is entirely driven by HIGH SCHOOL.SOME COLLEGE,and Ba DE- the perceived differences in the skill attributes of the GREE that are coded one if a respondent belongs immigrants.18 to the respective category of EDUCATION and zero In an additional experiment we replicated all our otherwise.Summary statistics for all variables used in tests based on within-group variation by using a cross- the analysis are provided in Appendix B. over design.For this follow-up test,we contacted a random subset of the respondents two weeks after they had completed the main survey.Half of these respon- Attitudes toward Highly and Low-skilled dents we randomly selected to receive the alternate version of the question they had received in the original Immigrants and Natives'Skill Levels survey two weeks prior.This approach allowed us to Figure 3 plots the distributions of preferences condi- compare the responses to both questions from the same tional on respondents'skill levels.The results suggest individual while minimizing the danger of"consistency two key findings.First,regardless of the respondents' bias."19 The results from the analysis of this follow-up skill level,highly skilled immigrants are strongly pre- experiment,which strongly confirm the results from ferred over low-skilled immigrants.Second,in stark the main experiment reported below,are described in contrast to the predictions based on the theoretical Appendix A. model,we find that support for both types of immi- gration is increasing(at a roughly similar rate)with re- spondents'skill level.For example,whereas only 7%of the least skilled respondents (those who did not finish high school)favor an increase in low-skilled immigra- Opposition to immigration among this group was lower than op- tion,29%favor an increase in highly skilled immigra- position to low-skilled immigration (in the pilot control group), tion.However,we find a similar preference differential and higher than opposition to highly skilled immigration (in the pilot treatment group).Because the results fell in the middle when among the most highly skilled respondents(those with no skill levels were specified,we focused on just the two con- at least a bachelor's degree):only 31%prefer an in- trasting versions of the question when we implemented the survey crease in low-skilled immigration but more than 50% experiment. prefer an increase in highly skilled immigration. 18 As a robustness check we also replicated both the labor market Taken together,these results are at odds with the competition and the fiscal burden tests,excluding respondents who chose the neutral,middle category.The results,which are available claim that concerns about labor market competition upon request,are virtually identical to the ones presented below are a driving force in shaping attitude toward immigra- where the middle category is included.Omitting the middle cate- tion.Instead,the results are consistent with previous gory leads,if anything,to an even stronger disconfirmation of the findings indicating that people with levels of higher conventional wisdom. 19 It is well known that if asked questions about similar issues all at education are more likely to favor immigration (for a once,respondents tend to make their answers consistent even when variety of other economic and noneconomic reasons) they would respond to the questions in substantially different ways regardless of immigrants'skill attributes(Hainmueller were they asked separately. and Hiscox 2007). 68
Attitudes toward Immigration February 2010 FIGURE 2. Support for Highly Skilled and Low-skilled Immigration Allow more low-skilled immigration? Allow more highly skilled immigration? Fraction 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Strongly agree Agree Neither agree nor disagree Disagree Strongly disagree Upper 95% confidence bound we know that this statistically significant difference between the two distributions is entirely driven by the perceived differences in the skill attributes of the immigrants.18 In an additional experiment we replicated all our tests based on within-group variation by using a crossover design. For this follow-up test, we contacted a random subset of the respondents two weeks after they had completed the main survey. Half of these respondents we randomly selected to receive the alternate version of the question they had received in the original survey two weeks prior. This approach allowed us to compare the responses to both questions from the same individual while minimizing the danger of “consistency bias.”19 The results from the analysis of this follow-up experiment, which strongly confirm the results from the main experiment reported below, are described in Appendix A. Opposition to immigration among this group was lower than opposition to low-skilled immigration (in the pilot control group), and higher than opposition to highly skilled immigration (in the pilot treatment group). Because the results fell in the middle when no skill levels were specified, we focused on just the two contrasting versions of the question when we implemented the survey experiment. 18 As a robustness check we also replicated both the labor market competition and the fiscal burden tests, excluding respondents who chose the neutral, middle category. The results, which are available upon request, are virtually identical to the ones presented below where the middle category is included. Omitting the middle category leads, if anything, to an even stronger disconfirmation of the conventional wisdom. 19 It is well known that if asked questions about similar issues all at once, respondents tend to make their answers consistent even when they would respond to the questions in substantially different ways were they asked separately. EMPIRICAL TEST I: THE LABOR MARKET COMPETITION MODEL Skill Levels of Natives If concerns about labor market competition are important in shaping attitudes toward immigration, we expect, in line with the FP model of attitude formation, that natives should oppose immigrants with similar skill levels but favor immigrants with different skill levels. That is, we expect that the skill levels of our survey respondents should have a large and positive relationship with support forlow-skilled immigrants and a large and negative effect on support for highly skilled immigrants. To conduct an explicit test of this argument, we follow previous studies and employ educational attainment as our measure of respondent skill levels (Facchini and Mayda 2009; Hanson, Scheve, and Slaughter 2007, 2008; Mayda and Rodrik 2005; Scheve and Slaughter 2001). This measure, which we label EDUCATION, is a categorical indicator of the highest level of education attained by the respondent. The coding is: 1 = Not completed high school education, 2 = High school graduate, 3 = Some college, 4 = Bachelor’s degree or higher. Alternatively, we also use a set of binary indicator variables called HS DROPOUT, HIGH SCHOOL, SOME COLLEGE, and BA DEGREE that are coded one if a respondent belongs to the respective category of EDUCATION and zero otherwise. Summary statistics for all variables used in the analysis are provided in Appendix B. Attitudes toward Highly and Low-skilled Immigrants and Natives’ Skill Levels Figure 3 plots the distributions of preferences conditional on respondents’ skill levels. The results suggest two key findings. First, regardless of the respondents’ skill level, highly skilled immigrants are strongly preferred over low-skilled immigrants. Second, in stark contrast to the predictions based on the theoretical model, we find that support for both types of immigration is increasing (at a roughly similar rate) with respondents’ skill level. For example, whereas only 7% of the least skilled respondents (those who did not finish high school) favor an increase in low-skilled immigration, 29% favor an increase in highly skilled immigration. However, we find a similar preference differential among the most highly skilled respondents (those with at least a bachelor’s degree): only 31% prefer an increase in low-skilled immigration but more than 50% prefer an increase in highly skilled immigration. Taken together, these results are at odds with the claim that concerns about labor market competition are a driving force in shaping attitude toward immigration. Instead, the results are consistent with previous findings indicating that people with levels of higher education are more likely to favor immigration (for a variety of other economic and noneconomic reasons) regardless of immigrants’ skill attributes (Hainmueller and Hiscox 2007). 68