Legislation

Analyzing the Effects of State Legislation on the Incidence of Abortion During the 1990s (2004)

Analyzing the Effects of State Legislation on the Incidence of Abortion During the 1990s

by Michael J. New, Ph.D.

Center for Data Analysis Report #04-01
January 21, 2004

The 1990s saw both the election and re-election of a "pro-choice" President.1 However, the "pro-life" movement made considerable gains at the state and local levels.

Survey data indicate that by the end of the decade, more people supported restrictions on abortion and fewer supported discretionary abortion.2

Meanwhile, the actual number of abortions declined during the decade.

For the 46 states reporting data to the Centers for Disease Control and Prevention in both 1990 and 1999,3 the number of abortions fell from 1,035,5734 to 854,416,5 a decline of 17.4 percent. This decline translates into a reduction in the abortion rate from 20.61 to 16.62 abortions per 1,000 women between the
ages of 15 and 44.6

What is the reason for this decline in the number of abortions? The economy, which grew at a brisk rate during the mid- to late 1990s, might be partly responsible.

Studies indicate that abortion rates decline during periods of strong economic growth.7

However, an even more directly related factor might be the impact of legislation intended to reduce the number of abortions.

This study used data from the Centers for Disease Control and Prevention (CDC) and the Alan Guttmacher Institute (AGI) to estimate how state-level "pro-life" legislation affected abortion rates and ratios.8

This paper reports a number of findings based on these data.

Among them:
Those states that adopted pro-life legislation during the 1990s experienced larger reductions in abortion rates and ratios than those states that did not adopt
such legislation.

State laws restricting the use of Medicaid funds in paying for abortions reduced the abortion rate by 29.66 and the abortion ratio by 2.08.

The CDC data indicate that states that adopted informed consent laws saw the abortion ratio drop by 11.69 and the abortion rate by 0.92.

When AGI data are used, statistical analysis indicates that informed consent laws have an even greater effect, reducing the abortion ratio by 22.46 and the abortion rate by 1.57.

Background
During the 1990s, there was a substantial amount of pro-life legislative activity at the state level. For instance:In 1992,9 virtually no states were enforcing informed consent laws.10  By 2000, 27 states had informed consent laws in effect.11 

In 1992, no states had banned or restricted the procedure widely known as "partial-birth abortion." By 2000, 12 states had bans or restrictions in effect.12

In 1992, only 20 states were enforcing parental involvement statutes.13 By 2000, 32 states were enforcing these laws.14

Two major factors led to this increase in pro-life legislation.

First, in 1992, the U.S. Supreme Court in Casey v. Planned Parenthood of
Southeastern Pennsylvania abandoned its trimester framework in favor of a doctrine of "undue burden." In so doing, the Court found constitutional some of the policies contained in Pennsylvania's Abortion Control Act. While the Supreme Court did not overturn Roe v. Wade, the decision did give pro-life legislators at the state level more freedom to enact laws designed to protect the unborn.

For instance, the only common forms of state-level legislation before the Casey decision that consistently withstood constitutional scrutiny were parental
involvement requirements and restrictions on Medicaid funding of abortions. However, Casey gave constitutional protection to informed consent laws.

These laws require abortion providers to inform pregnant women about the health risks associated with abortion, the development of their unborn children, and resources for pregnant women and young mothers.

Additionally, a number of states passed "partial-birth abortion" bans before the Supreme Court struck down Nebraska's ban in Stenberg v. Carhart in 2000.

Second, pro-life candidates made considerable and lasting gains in state legislatures during the 1990s. While it is well-known that Republicans obtained control of both the U.S. House of Representatives and the U.S. Senate in 1994, the gains they made in the states have received considerably less attention.

Republicans obtained majority control in both chambers of 11 additional state legislatures in 1994.15 Overall, the number of states where Republicans controlled both chambers of the state legislature increased from six in 1990 to 18 in 2000.16

In 2001, Republican state party platforms for 48 of 50 states contained planks that supported restrictions on abortion.17

Other Research

What impact has all of this legislation had? Some academic studies provide insights.

Much of the academic literature that examines the impact of state abortion
policy focuses on parental consent legislation and the extent to which states fund abortion through Medicaid. Most of these studies argue that parental consent
statutes and restrictions on Medicaid funding reduce the number of abortions that take place within the boundaries of a given state.18

However, researchers are considerably more divided over whether or not these laws create overall reductions in the number of abortions. This is because it is possible for some people to circumvent these laws by obtaining abortions in other states where the laws are more
permissive.

In "Mandatory Parental Involvement in Minors' Abortions: Effects of the Law in Minnesota, Missouri, and Indiana," Charlotte Ellertson, President and Chief
Executive Officer of Ibis Reproductive Health, pays special attention to the impact of Missouri's parental consent law.19

She finds that the number of abortions performed on minors decreased in Missouri after the passage of the parental consent law.20 However, she also found that minors were more likely to travel to other states to obtain abortions.21

In the article, Ellertson argues that this increase in travel could be large enough to offset the reduction in the number of abortions in Missouri.22

Conversely, other studies arrive at different conclusions. One study indicates that the number of abortions performed on Mississippi residents, both in state and out
of state, declined after the state's parental consent statute was passed.23

Similarly, other studies that have examined Minnesota's parental notification law have found little evidence that minors are leaving the state in great numbers to obtain abortions.24

While these studies shed light on the abortion patterns of the 1990s, many shortcomings exist.

First and foremost, none of the studies examines the impact of "partial-birth abortion" bans or informed consent statutes. Of course, some of the earlier
studies examine a time frame where few, if any, states had such laws. However, even some of the later studies neglect to analyze their impact.25

Second, state abortion data come from two sources, the Centers for Disease Control and Prevention and the Alan Guttmacher Institute.26 Most studies are limited because they use only one of these data sources, each of which has shortcomings.

The Guttmacher Institute receives its data from surveys of abortion clinics. While its method of data collection is more consistent than the CDC's, the AGI does not
collect data every year. Conversely, the CDC does provide annual data, but its data typically come from state health agencies. Since state health agencies often change their methods for collecting and disseminating data, their data may be
somewhat less reliable.

Finally, many of these studies have a very limited scope, examining only a small number of states that have enacted these policies.27 This can lead to problems of selection bias. Still others consider only data from relatively few years.28 As a result, these studies may not have sufficient data to draw statistically meaningful comparisons.

This analysis attempts to overcome these limitations. It presents data on abortion rates and ratios in every state from 1985 to 1999, using data from both the CDC and the AGI. Furthermore, it takes into account the impact of informed consent laws and "partial-birth abortion" bans.

Finally, it holds constant economic and demographic factors that might cause fluctuations in the number of abortions.

Methodology
The empirical test of the effectiveness of

pro-life legislation involves a series of

regressions on a dataset that includes

statistics on abortions for the years 1985

through 2000. Regression analysis is

well-suited to this type of research because

it simultaneously examines the effects of

various factors on the number of abortions

in each state.

Separate regressions were run on four

dependent variables measuring the

number of abortions within a given state.

The first set of dependent variables

measure the state abortion ratio as

indicated by the CDC and Alan Guttmacher

Institute, respectively. The abortion ratio

measures the number of abortions for

every 1,000 births. The second set of

dependent variables measure the state

abortion rate as indicated by the CDC and

AGI. These variables measure the number

of abortions per 1,000 women between

the ages of 15 and 44. Combined, these

four dependent variables should help

determine the impact of various forms of

pro-life legislation.

A variety of economic and demographic

factors are held constant. To capture the

impact of the economy, this study includes

each state's per capita personal income

growth in the regression model.

Additionally, a series of state-level variables

measuring the racial composition of

women between the ages of 15 and 44

are included in the model as well.

Three separate variables measure the

percentage of women of childbearing

age29 who are between the ages of 15 to

19, 20 to 25, and 25 to 29, respectively.

The hypothesis is that younger women

facing unexpected pregnancies would be

more likely to seek abortions than their

older counterparts. As a result, holding

other factors constant, relatively higher

percentages of younger women would lead

to increases in both abortion rates and

abortion ratios.

Finally, a fertility variable, measuring the

number of births per 1,000 women

between the ages of 15 and 44, is included

in the model. This variable serves as a

proxy for the number of pregnancies that

are occurring. Fewer pregnancies would

result in fewer abortions. Similarly, if the

fertility variable is low, it might indicate that

a higher proportion of pregnancies are

planned, which would also result in fewer

abor-tions.

Of more interest in this study is the effect of

different types of state policies that deal

di-rectly with access to abortion. The

re-gression analysis in-cludes four separate

variables indicating the presence or

ab-sence of a particular type of policy.

The first of these variables is the presence

of a parental involvement requirement.30

Parental notification requirements require

minors either to notify or to receive

consent from one or both parents before

receiving an abortion.

The second policy variable is whether or

not a state restricts funding of therapeutic

abortions through Medicaid. Most states

will fund abortions through Medicaid when

the pregnancy is the result of rape.

Similarly, most states fund abortions that

are necessary to preserve the life of the

mother. However, states differ as to

whether they fund therapeutic abortions.

Third is whether or not a state has an

informed consent statute. In Casey v.

Planned Parenthood (1992), the Supreme

Court found that informed consent statutes

were constitutional. Informed consent

statutes differ from state to state.

However, they all require women seeking

abortions to receive information about the

abortion procedure. This can include

information about fetal development, the

health risks involved with obtaining an

abortion, and the public and private

sources of support for single mothers.

The fourth and final policy variable is

whether a state has a ban on "partial-birth

abortions." About 12 states had

"partial-birth abortion" bans in effect

between 1996 and 2000 before the

Supreme Court struck down Nebraska's

"partial-birth abortion" ban in Stenberg v.

Carhart in 2000…

Discussion
Overall, the results from the regression

analysis indicate that pro-life legislation has

been effective at reducing the incidence of

abortion at the state level. In particular,

Medicaid funding restrictions appear to be

especially effective at reducing the number

of abortions. When data from the CDC are

used, the model predicts that Medicaid

funding restrictions reduce the abortion

rate by 29.67 and the abortion ratio by

2.08. Moreover, these results are

statistically significant.33 Furthermore,

when AGI data are used, the magnitude

and significance of these coefficients are

similar. Overall, these findings are

consistent with much of the academic

literature that examines the impact of

Medicaid funding restrictions.

Of particular interest is the impact of

informed consent laws. These laws are a

recent policy innovation, and none of the

other academic studies examines their

impact. When the CDC data are used, the

regression indicates that the passage of an

informed consent law reduces the abortion

ratio by 11.69 and the abortion rate by

0.92. When AGI data are used, the results

indicate that informed consent laws have

an even greater effect, reducing the

abortion ratio by 22.46 and the abortion

rate by 1.57. All of these results are

statistically significant. These findings are

particularly interesting because over 20

states adopted informed consent laws

between 1992 and 1999.34 It seems

likely that these laws played an especially

large role in the decline in abortions during

the 1990s.

Parental involvement laws appear

somewhat less effective than the other

types of public policies. In all four of the

models, the coefficient for the parental

involvement laws is negative, which is

consistent with expectations. However,

while some of the coefficients approach

statistical significance, none actually

reaches it. It should also be noted that

parental involvement laws limit only the

ability of minors to have abortions.

Examining their impact on minors who

undergo abortions, instead of all women

who undergo abortions, would be a better

test of the effectiveness of such laws. Even

so, parental involvement laws do appear to

reduce overall abortion rates and ratios,

but their impact is less statistically certain

than the impact of Medicaid funding

restrictions and informed consent laws.

Finally, all the models predict that

"partial-birth abortion" bans reduce

abortion rates and ratios. In two of the four

models, the coefficients do not achieve

statistical significance. However, it should

be noted that the first "partial-birth

abortion" law was not enacted until 1996,

and most "partial-birth abortion" bans went

into effect in 1997 and 1998.35 As a

result, there are relatively few data with

which to evaluate their effectiveness.

Conclusion
The number of abortions rose consistently

throughout the 1970s and the 1980s.36

However, that trend reversed during the

1990s as the number of legal abortions

declined by 17.4 percent between 1990

and 1999.37

There are a number of different reasons

for this decline. However, one factor that

cannot be overlooked is the impact of

pro-life legislation in the states. By the end

of the decade, more states had adopted

parental involvement requirements,

informed consent requirements, and

"partial-birth abortion" bans.38 More

important, regression results provide

evidence that each of these laws was

effective at reducing the number of

abortions that took place.

Michael J. New, Ph.D., is a post-doctoral

fellow at the Harvard-MIT Data Center.

Appendix A: Regression Results
Regression analysis allows examination of

the effects of various factors on the central

concern of this paper: state-level abortion

rates and ratios. Regression analysis sorts

out the effects of a single variable by

holding constant the effects of all other

variables. Appendix A provides the

coefficients and standard errors for the

various regression models.

The coefficient of the independent variables

provides an estimate of how much a

one-unit change of the independent

variables changes the dependent variable.

For instance, when data from the Centers

for Disease Control are used, the

regression model predicts that a 1

percentage point increase in state

personal income growth will reduce the

state abortion ratio by 0.94 abortions per

1,000 live births and will reduce the state's

abortion ratio by 0.10 abortions per 1,000

women between the ages of 15 and 44.

Similarly, when CDC data are used, the

regression model predicts that the

passage of a parental involvement law will

lower the state abortion ratio by 7.22

abortions for every 1,000 births and lower

the state abortion rate by 0.54 abortions

per 1,000 women between the ages of 15

and 44…

Data Sources
The following states did not report data to

the Centers for Disease Control and

Prevention in 1998 and 1999: Alaska,

California, New Hampshire, and Oregon.

Data from Alaska are omitted because of

data collection problems. Data from

Kansas are omitted as well. According to

the CDC data, the abortion rate jumped an

astounding 69 percent between 1991 and

1999, and this cannot be traced to any

shifts in economics, policy, or

demographics in Kansas or in neighboring

states. Instead, it appears that a large

number of women seeking abortions

choose to travel to Kansas. Indeed, for

every year between 1992 and 1999, the

CDC reports that over 40 percent of the

abortions in Kansas are performed on

out-of-state residents. This is by far the

highest figure for an

y state.

Nearly all states reported abortion data to

the CDC through their central health

agency. However some state data were

obtained from hospitals and other medical

facilities. Since these differences in

reporting may bias the results, data from

the following states and years are omitted

from CDC models:

Alabama 1981-1990

Iowa 1981-1997

New Hampshire 1981-1997

West Virginia 1981-1998

Illinois 1984-1987

Kentucky 1984-1986

Oklahoma 1984-1997

The Alan Guttmacher Institute released

state abortion data in the following eight

years: 1985, 1987, 1988, 1991, 1992,

1995, 1996, and 2000. Data from Alaska

are omitted because of data collection

problems. Data from Kansas are omitted

because of the same outlier problems

described above.

1. Legislation intended to reduce legal

barriers to abortion and those who support

such legislation are often referred to as

"pro-choice," while legislation intended to

reduce the number of abortions and those

who support such legislation are often

called "pro-life." These widely accepted

terms are used throughout this study.

2. Lydia Saad, "Public Opinion About

Abortion, An In-Depth Review," Gallup Poll

Special Report, at
www.gallup.com/poll/specialreports/pollS

ummaries/sr020122.asp.

3. Alaska, California, New Hampshire, and

Oregon did not report data in 1999.

4. Centers for Disease Control and

Prevention, Morbidity and Mortality Weekly

Report, December 17, 1993, Vol. 42, pp.

34-35. Calculations by author.

5. Laurie D. Elam-Evans, Lilo T. Strauss, Joy

Herndon, Wilda Y. Parker, Sara Whitehead,

and Cynthia J. Berg, "Abortion

Surveillance–United States, 1999," Centers

for Disease Control and Prevention,

Morbidity and Mortality Weekly Report,

November 29, 2002, at

www.cdc.gov/mmwr/preview/mmwrhtml

/ss5109a1.htm. Calculation by author.

6. The abortion rate is the number of

abortions per 1,000 women between the

ages of 15 and 44.

7. See Rebecca Blank, Christine George,

and Rebecca London, "State Abortion

Rates: The Impact of Policies Providers,

Politics, Demographics, and Economic

Environment," Journal of Health Economics,

Vol. 15 (1996), pp. 513-553.

8. The abortion ratio is the number of

abortions per 1,000 live births.

9. Prior to 1992, courts struck down most

informed consent laws; however, a few

fairly weak laws remained in effect.

10. NARAL Foundation, Who Decides?

1992, p. 9.

11. NARAL Foundation, Who Decides?

2000, p. 125.

12. Ibid.

13. NARAL Foundation, Who Decides?

1992, p. 125.

14. NARAL Foundation, Who Decides?

2000, p. 125.

15. Bureau of the Census, Statistical

Abstract of the United States: 2001

(Washington, D.C.: U.S. Government

Printing Office, 2000), p. 249.

16. Ibid.

17. NARAL Foundation, Who Decides?

2001, pp. 262-263.

18. Deborah Haas-Wilson, "The Impact of

State Abortion Restrictions on Minors'

Demand for Abortions," The Journal of

Human Resources, Vol. 31, No. 1 (1996),

pp. 140-158; Deborah Haas-Wilson, "The

Economic Impact of State Policy

Restrictions on Abortion: Parental Consent

and Notification Laws and Medicaid Funding

Restrictions," Journal of Policy Analysis and

Management, Vol. 12, No. 3 (1993), pp.

498-511; Patricia Donovan, "Judging

Teenagers: How Minors Fare When They

Seek Court Authorized Abortions," Family

Planning Perspectives, Vol. 15, No. 6

(1983), pp. 259-267; Rebecca Blank,

Christine George, and Rebecca London,

"State Abortion Rates: The Impact of

Policies Providers, Politics, Demographics,

and Economic Environment," National

Bureau of Economic Research Working

Paper No. 4853, 1994; and Robert

Ohsfeldt and Stephan Gohman, "Do

Parental Involvement Laws Reduce

Adolescent Abortion Rates?"

Contemporary Economic Policy, Vol. 12, No.

2 (1994), pp. 65-76.

19. Charlotte Ellertson, "Mandatory

Parental Involvement in Minors' Abortions:

Effects of the Laws in Minnesota, Missouri,

and Indiana," American Journal of Public

Health, Vol. 87, No. 8 (1997), pp.

1367-1374.

20. Ibid., p. 1373.

21. Ibid.

22. Ibid., pp. 1371-1372.

23. Stanley K. Henshaw, "The Impact of

Requirements for Parental Consent on

Minor's Abortions in Mississippi," Family

Planning Perspectives, Vol. 27, No. 3

(1995), pp. 120-122.

24. Patricia Donovan, "Judging Teenagers:

How Minors Fare When They Seek Court

Authorized Abortions," Family Planning

Perspectives, Vol. 15, No. 6 (1983), pp.

259-267; Robert Blum, Michael Resnick,

and Trisha Stark, "The Impact of a Parental

Notification Law on Adolescent Abortion

Decision Making," American Journal of

Public Health, Vol. 77, No. 5 (1987), pp.

619-620.

25. Rebecca Blank, Christine George, and

Rebecca London, "State Abortion Rates:

The Impact of Policies Providers, Politics,

Demographics, and Economic

Environment," Journal of Health Economics,

Vol. 15 (1996), pp. 513-553; Anita

Prichard and Sharon Kay Parsons, "The

Effects of State Abortion Policies on States'

Abortion Rates," State and Local

Government Review, Vol. 31, No. 1 (1999),

pp. 43-52.

26. The Alan Guttmacher Institute, named

for a former president of Planned

Parenthood, is a nonprofit organization

focused on sexual and reproductive health

research. Its mission includes the

advancement of reproductive rights.

27. Virginia Cartoof and Lorraine Klerman,

"Parental Consent for Abortion: Impact of

the Massachusetts Law," American Journal

of Public Health, Vol. 76, No. 4 (1986), pp.

397-400; Patricia Donovan, "Judging

Teenagers: How Minors Fare When They

Seek Court Authorized Abortions," Family

Planning Perspectives, Vol. 15, No. 6

(1983), pp. 259-267; Robert Blum,

Michael Resnick, and Trisha Stark, "The

Impact of a Parental Notification Law on

Adolescent Abortion Decision Making,"

American Journal of Public Health, Vol. 77,

No. 5 (1987), pp. 619-620; James Rogers,

Robert Boruch, George Storms, and

Dorothy DeMoya, "

Impact of the Minnesota

Parental Notification Law on Abortion and

Birth," American Journal of Public Health,

Vol. 81, No. 3 (1991), pp. 294-298.

28. Deborah Haas-Wilson, "The Economic

Impact of State Policy Restrictions on

Abortion: Parental Consent and Notification

Laws and Medicaid Funding Restrictions,"

Journal of Policy Analysis and

Management, Vol. 12, No. 3 (1993), pp.

498-511.

29. For the purposes of this study, women

of childbearing age are defined as those

women between the ages of 15 and 44.

30. Both parental consent and parental

notification statutes are considered

parental involvement requirements.

31. A fixed effect model allows examination

of the within-state effects of pro-life

legislation. By holding the individual states

constant, the regression compares the

abortion rate after legislation was passed

to the abortion rate before legislation was

passed and determines whether the

differences are statistically significant.

32. The regression models that use AGI

data predict that partial-birth abortion bans

result in much larger reductions in

abortion rates and ratios than are

predicted by the regression models that

use CDC data. This is likely because the AGI

data consist of only one year (2000) during

which partial-birth abortion bans were in

effect. As a result, it is possible that the

partial-birth abortion ban variable is picking

up reductions caused by unaccounted for

factors or random effects. Conversely, the

CDC dataset includes data from three

years where states had enacted

partial-birth abortion bans (1997, 1998,

1999). Since the CDC dataset contains

more years, it is believed that their

prediction about the impact of partial-birth

abortion bans is more accurate.

33. a variable is statistically significant if

there is at least a 90 percent certainty that

the given variable has a non-zero effect on

abortion rates or abortion ratios

34. NARAL Foundation, Who Decides?

1992, pp. 125-127, and Who Decides?

2000, pp. 125-127.

35. NARAL Foundation, Who Decides?

1991-2000.

36. Elam-Evans et al., "Abortion

Surveillance."

37. Centers for Disease Control and

Prevention, Morbidity and Mortality Weekly

Report, December 17, 1993, pp. 34-35,

and Elam-Evans et al., "Abortion

Surveillance." Calculation by author.

38. NARAL Foundation, Who Decides?

1992, pp. 125-127, and Who Decides?

2000, pp. 125-127.
[by Michael J. New, Ph.D.
Center for Data Analysis Report #04-01
January 21, 2004]