Quarterly journal of economics
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account for less than 20 percent of overall arrests. Second, states that legalized abortion in 1970 continued to have higher abortion rates even after Roe v. Wade. For instance, in 1976, three years after Roe v. Wade was handed down, the early-legalizing states 21. It is worth noting one ostensible inconsistency between our predictions and the disaggregated time-series data. As noted by Cook and Laub [1998] and Blumstein and Rosenfeld [1998], there was a sharp spike in youth homicide rates in the late 1980s and early 1990s, especially among African-Americans. These cohorts were born after legalized abortion. Importantly, this nding is not incon- sistent with the central claim that abortion legalization contributed to lower crime rates, but merely shows that this dampening effect on crime can be outweighed in the short term by factors that stimulate crime. Elevated youth homicide rates in this period appear to be clearly linked to the rise of crack and the easy availability of guns. That abortion is only one factor in uencing crime in the late 1980s points out the caution required in drawing any conclusions regarding an abortion-crime link based on time-series evidence alone. 22. Evidence in Levine et al. [1996] suggests that there was a substantial amount of border crossing in order to obtain legal abortions prior to 1973. To the extent that is true, the observed differences in crime between early-legalizing states and all others will be muted. It appears, however, that the more af uent tended to travel for abortions, which probably diminishes the importance of such activity for assessments about crime. Some evidence of this is seen in the fact that abortions performed in New York on white women were cut in half in the wake of the decision in Roe v. Wade, but there was a far smaller drop in the number of abortions performed in New York on black women. 395
had a 1985 population-weighted average rate of 593 abortions per live births, compared with 308 for all other states. Given that the impact of abortion on crime happens only gradually, it is dif cult to disentangle the separate impacts of early legalization and higher steady state abortion rates. 23 Bearing in mind these important caveats, a comparison of crime trends in early-legalizing and all other states is displayed in Table I, as well as the difference between those two values. For each of three crime categories (violent, property, murder), we present percent changes in crime by six-year periods for the years 1976 –1994, and for the period 1994 –1997. The bottom panel of the table also presents the effective abortion rate for violent crime for the two sets of states at the end of each time period, computed using equation (1). 24 Prior to 1982, legalized abortion should have no impact on crime since the rst cohort affected by abortion is no more than twelve years old. These years are included as a check on any preexisting trends in crime rates across the two sets of states. As Table I shows, these preexisting trends are not statistically dif- ferent across early-legalizing and all other states, nor is the relative pattern constant across the three crime categories. Both property and violent crime were increasing at a slower rate in early legalizing states between 1976 and 1982, whereas murder was rising faster in early-legalizing states. As shown in the bottom panel of Table I, by 1988 the effective abortion rate for violent crime in early-legalizing states was 64.0 compared with 10.4 in the rest of the United States. To explore whether crime rates began to respond to early abortion legalization between 1982 and 1988, look at the rows labeled “Difference” in the 1982–1988 column. A negative sign for this difference suggests that crime fell faster in the states that le- galized abortion earlier (consistent with the theory of this pa- per), while a positive sign suggests the opposite. Here we see the evidence of the impact of early legalization for the 1982– 23. From the broader perspective of determining whether crime rates re- spond to abortion, this distinction may be irrelevant. However, the inability to distinguish the two channels of impact lessens the extent to which a comparison of early legalizers to other states represents a distinct source of variation from the regression analysis using abortion rates across states after 1973. 24. The effective abortion rate for violent crime falls between the correspond- ing measures for property crime and homicide. The pattern of differences is similar for the other crime categories, except that the gap rises more (less) quickly for property crime (homicide). 396
1988 period is mixed. Property crime fell signi cantly in early- legalizing states relative to the rest of the United States (2 9.8 percentage points), and the difference is more than twice as large as the preexisting trend in the rst column. There is no apparent impact on violent crime or murder by 1988. Nonetheless, the earlier impact on property crime is consistent with the fact that offenses committed by the very young are disproportionately con- centrated in property crime. For instance, in 1995 those under age eighteen accounted for over one-third of all property crime arrests, but less than 20 percent of violent crime and murder arrests. TABLE I
C RIME
T RENDS FOR S TATES
L EGALIZING A BORTION
E ARLY VERSUS THE R
U NITED
S TATES
Crime category Percent change in crime rate over the period Cumulative, 1982–1997 1976–1982 1982–1985 1988–1994 1994–1997 Violent crime Early legalizers 16.6 11.1
1.9 2 25.8 2 12.8
Rest of U. S. 20.9
13.2 15.4
2 11.0
17.6 Difference 2 4.3
2 2.1
2 13.4
2 14.8
2 30.4
(5.5) (5.4)
(4.4) (3.3)
(8.1) Property crime Early legalizers 1.7
2 8.3
2 14.3
2 21.5
2 44.1
Rest of U. S. 6.0
1.5 2 5.9 2 4.3
2 8.8
Difference 2 4.3 2 9.8
2 8.4
2 17.2
2 35.3
(2.9) (4.0)
(4.2) (2.4)
(5.8) Murder
Early legalizers 6.3
0.5 2.7
2 44.0
2 40.8
Rest of U. S. 1.7
2 8.8
5.2 2 21.1 2 24.6
Difference 4.6
9.3 2 2.5 2 22.9
2 16.2
(7.4) (6.8)
(8.6) (6.8)
(10.7) Effective abortion rate at end of period Early legalizers 0.0 64.0
238.6 327.0
327.0 Rest of U. S. 0.0 10.4
87.7 141.0
141.0 Difference 0.0 53.6
150.9 186.0
186.0 Early legalizing states are Alaska, California, Hawaii, New York, and Washington. These ve states legalized abortion in late 1969 or 1970. In the remaining states, abortion became legal in 1973 after Roe v.
of the natural log of the crime rate at the beginning of the period from the xed 1985 population-weighted average of the natural log of the crime rate at the end of the period. The rows labeled “Difference” are the difference between early legalizers and the rest of the United States (standard errors are reported in parentheses). The bottom panel of the table presents the effective abortion rate for violent crime, as calculated using equation (1) in the text, based on the observed age distribution of national arrests for violent crime in 1985. Entries in the table are xed 1985 population-weighted averages of the states. Abortion data are from the Alan Guttmacher Institute; crime data are from Uniform Crime Reports. Because of missing crime data for 1976, the 1976 –1982 calculations omit the District of Columbia. Precise data sources are provided in the Data Appendix. 397
By 1994, the gap in the “effective abortion rate” between early-legalizing states and all others had grown to 150.9. The early-legalizing states experienced declines in crime relative to the rest of the United States in all three crime categories. The trend accelerates between 1994 and 1997, with double-digit (and highly statistically signi cant) differences for each of the crimes. The last column of Table I shows that the cumulative decrease in F IGURE IVa Changes in Violent Crime and Abortion Rates, 1985–1997 F IGURE
IVb Changes in Property Crime and Abortion Rates, 1985–1997 398
crime between 1982–1997 for early-legalizing states compared with the rest of the nation is 16.2 percent greater for murder, 30.4 percent greater for violent crime, and 35.3 percent greater for property crime. Realistically, these crime decreases are too large to be attributed to the three-year head start in the early-legaliz- ing states. Put another way, the observed differences in the “effective abortion rate” documented in the bottom of Table I re ect not only the head start on abortion, but also higher steady state rates. Thus, the source of variation exploited in Table I is not entirely distinct from that used in the state-level panel re- gressions below.
The preceding discussion provides suggestive evidence of an impact of abortion on crime. In what follows, we explore this relationship more systematically by using a panel data analysis F IGURE
IVc Changes in Murder and Abortion Rates, 1985–1997 The vertical axis in Figures IVa–IVc corresponds to the log change in the named crime category between 1985 and 1997. The horizontal axis is the change in the effective abortion rate corresponding to the crime category between 1985 and 1997. The effective abortion rate is the estimated average abortion rate per 1000 live births for criminals in the state, as calculated using equation (1) in the text. Washington, DC, which is an extreme outlier with respect to abortion rates, is omitted from the gures, but is included in all other statistical analyses. 399
LEGALIZED ABORTION AND CRIME to relate state abortion rates after Roe v. Wade to state-level changes in crime over the period from 1985 through 1997. Before presenting regression results, Figures IVa–IVc show simple plots of log-changes in crime rates between 1985 and 1997 against the change in the state-level effective abortion rate over that same time period. 25 The three gures correspond to violent crime, property crime, and murder, respectively. In each case, there is a clear negative relationship between crime changes over the period 1985–1997 and abortion rates in the years immedi- ately following Roe v. Wade. The tted population-weighted re- gression lines are also included in the gures. The R 2 from these simple regressions range from .12 (murder) to .45 (property crime), as re ected in the relatively tighter t of the regression line for the latter crime category. The raw relationship between abortion rates in the 1970s and falling crime in the 1990s emerges even more clearly in Table II. States are ranked based on effective abortion rates in 1997 and 25. The gures plot the scatter diagrams for all 50 states. The District of Columbia is dropped from the graph, as it is an extreme outlier that does not accurately re ect the abortion rates of D.C. residents, as indicated in footnote 27, below. All states had effective abortion rates close to zero in 1985, so the change in the effective abortion rate between 1985 and 1997 is almost identical to the effective abortion rate in 1997. TABLE II C RIME C HANGES
1985–1997 AS A
F UNCTION OF A BORTION
R ATES
1973–1976 Abortion
frequency (Ranked by effective abortion rate in 1997) Effective abortions per 1000
live births, 1997
% Change in crime rate, 1973–1985 % Change in crime rate, 1985–1997 Violent crime
Property crime
Murder Violent
crime Property
crime Murder
Lowest 67.5
+ 31.8 + 29.8
2 21.1
+ 29.2 + 9.3
+ 4.1 Medium
135.0 + 28.8
+ 31.1 2 19.7 + 18.0 + 2.2
2 12.6
Highest 257.1
+ 32.2 + 15.2
2 9.7
2 2.4
2 23.1
2 25.9
States are ranked by effective abortion rates for violent crime in 1997, with the seventeen states with lowest abortion rates classi ed as “lowest,” the next seventeen states classi ed as “medium,” and the highest seventeen states (including District of Columbia) classi ed as “highest.” The effective abortion rate is the estimated average abortion rate per 1000 live births for criminals in the state, as calculated using equation (1) in the text, based on the observed age distribution of national arrests for violent crime in 1985. All values in the table are weighted averages using 1985 state populations as weights. Percent change in crime per capita is calculated by subtracting the xed 1985 population-weightedaverage of the natural log of the crime rate at the beginning of the period from the xed 1985 population-weightedaverage of the natural log of the crime rate at the end of the period. Because crime rates are extremely low until the midteenage years, legalized abortion is not predicted to have had a substantial impact on crime over the period 1973–1985, but would be predicted to affect crime in the period 1985–1997. Abortion data are from the Alan Guttmacher Institute; crime data are from Uniform Crime Reports. Precise data sources are provided in the Data Appendix. 400
QUARTERLY JOURNAL OF ECONOMICS divided into three categories: low, medium, and high. Mean ef- fective abortion rates, and percent changes in murder, violent crime, and property crime for the periods 1973–1985 and 1985– 1997 are shown in the table for the three sets of states. Crime data for the period 1973–1985 are included as a check on the validity of the results. There should be no effect of abortion on crime between 1973–1985. To the extent that high and low abor- tion states systematically differ in the earlier period, questions about the exogeneity of the abortion rate are raised. It is reas- suring that the data reveal no clear differences in crime rates across states between 1973 and 1985 as a function of the abortion rate. In some instances crime was rising more quickly in high abortion states; in other cases the opposite is true. For the period 1985–1997, however, the results change dramatically. For each crime category, the high abortion states fell relative to the low abortion states by at least 30 percentage points. In every in- stance, the medium abortion states had intermediate outcomes with respect to crime. The panel data regressions that we report are similar in spirit to Figure IV and Table II, but utilize not only the endpoints of the sample, but also information from the intervening years, as well as including a range of controls: (2) ln(CRIME st ) 5 b 1
st 1
st Q 1 g s 1 l t 1 e st , where s indexes states and t re ects time. The left-hand-side variable is the relevant logged crime rate per capita. Our measure of abortion is the effective abortion rate (de ned earlier) for a given state, year, and crime category. 26
controls that includes prisoners and police per capita, a range of variables capturing state economic conditions, lagged state wel- fare generosity, the presence of concealed handgun laws, and per capita beer consumption. g s and l
t represent state and year xed effects. All regressions are weighted least squares with weights based on state populations. All of the estimates we present are adjusted for serial correlation in panel data using the method of Bhargava et al. [1982]. 27 26. The weights used in computing the effective abortion rates are the per- centage of arrests by age for a given crime category in the United States in 1985. In other words, abortion rates are state-speci c, but the same weighting function is used for all states. 27. Blank, George, and London [1996] suggest that the of cial abortion rate in Washington, DC is arti cially elevated because women from Maryland and Virginia frequently travel there to receive abortions. The CDC estimates that 401
Summary statistics for the sample are provided in Table III. The summary statistics on abortion correspond to the effective abortion rate, which is well below the actual abortion rate throughout the sample because much of the criminal population was born prior to legalized abortion. Actual national abortion rates in the years immediately after Roe v. Wade were roughly 300 abortions per 1000 live births, but with considerable varia- tion across states. For example, over the period from 1973–1976, West Virginia had the lowest abortion rate (10 per 1000 live births), while New York (763) and Washington, D.C. (1793) had the highest rates. There is a great deal of variation in crimes per 1000 residents, both across states and within states over time. The same is true for arrest rates. An important limitation of the data is that state abortion rates are very highly serially correlated. The correlation between state abortion rates in years t and t + 1 is .98. The ve-year and ten-year correlations are .95 and .91, respectively. One implica- tion of these high correlations is that it is very dif cult using the data alone to distinguish the impact of 1970s abortions on current crime rates from the impact of 1990s abortions on current crime rates; if one includes both lagged and current abortion rates in the same speci cation, standard errors explode due to multicol- linearity. Consequently, it must be recognized that our interpre- tation of the results relies on the assumption that there will be a fteen-to-twenty year lag before abortion materially affects crime. This lag between the act of abortion and its impact on crime differentiates it from many other social phenomena like divorce and poverty which may have both lagged and contempo- raneous effects, making it very dif cult to separately identify any lagged effects. Regression results are shown in Table IV. For each of the three crime categories, two different speci cations are reported. The odd-numbered columns present results without control vari- ables (other than the state- and year- xed effects); the even columns add the full set of controls. The top row of the table presents the coef cients on the abortion variable across speci cations. In all six cases, the coef- cient is negative, implying that higher abortion rates are asso- about half of all abortions performed in the District of Columbia are on nonresi- dents (which is the highest percentage for any state); the comparable percentage in New Jersey is 2 percent [Dye and Presser 1999, p. 143]. 402
QUARTERLY JOURNAL OF ECONOMICS ciated with declining crime. These estimated effects of abortion are highly statistically signi cant—more so than any other vari- able included in the analysis. The real-world magnitude implied TABLE III S UMMARY
S TATISTICS Variable Mean
Standard deviation (overall) Standard
deviation (within state) Violent crime per 1000 residents 6.73
2.81 .88
Property crime per 1000 residents 48.04
11.46 4.60
Murder per 1000 residents 0.09
0.04 0.02
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