Lecture 9: Fertility Flashcards
Sammanfatta Grönqvist (2012)
This paper investigates the consequences of a series of Swedish policy changes in which several regions in the 90s introduced heavily subsidized oral contraception for teenagers.
DDD
The results reveal that access to the subsidy significantly increased the use of the pill as well as reduced the abortion and teenage birth rate.
The decline in teenage births was especially strong among financially constrained youths. The estimates are precise enough to rule out even moderate effects on the birth weight of the children to the exposed mothers.
Vad är variationen i Grönqvist’s (2012) studie?
Olika kommuner implementerar subvensionen vid olika tillfällen. Men det var också en variation i vilka cohorter av kvinnor som hade tillgång till den i olika kommumer.
VI har alltså variation i space (municipality), time(implemention date) and age (who is elegible).
Vad är first stage i Grönqvist’s (2012) studie? Vilken effekt ser han och vilket placebo-test gör han?
Om policyn påverkade konsumtionen är vår first stage vilket är det första vi vill veta. Han studerar detta genom detaljerad ”prescription data”.
Substitutionen gjorde så att försäljningen ökade med ca 6%.
Han gör placebotest genom att assigna treatment time tidigare, man ser då att det inte är. Någon effekt. Han estimerar även en DDD av first stage där han också använder kvinnor som är för gamla för subventionen som en extra kontrollgrupp.
Vad är Grönqvists estimeringsstrategi?
The first part of the empirical analysis relies on data on the total amount of oral
contraception sold in each county and year to identify the impact of the subsidy on contraceptive use. Controlling for fixed regional differences in the demand and supply of oral contraception, the results reveal that the subsidy increased total sales by about 5.5 percent. An auxiliary analysis using an independent data source containing information on self-reported consumption shows that the increase was largely driven by teenagers’ use of the pill.
By drawing on the fact that the subsidy was only offered to young women, the data make it possible to control for most potential confounding factors. The strategy is to compare the outcomes of eligible versus ineligible age groups in regions where the subsidy was in place, and contrast these differences to those in areas where the subsidy still had not been introduced. The benefit of this differences-in-differences-in-differences estimator is that it controls for all unobserved factors that may be correlated with the timing of the adoption of the subsidy as long as these do not affect the relative outcomes between different age groups. The results show that the subsidy significantly reduced the abortion rate by about 8.8 percent. There is however no evidence that it affected birth weight and the precise estimates makes it possible to rule out even moderate effect sizes.
The effect is significantly stronger for women from worse socioeconomic background.
Först studerar han first stage på aggregerad nivå. Sedan går han vidare och studerar mödrarnas utfall på lång sikt med individdata.
Han studerar då sannolikheten att en kvinnas första barn föddes då hon var 20, antalet barn kvinnan har och sannolikheten att kvinnans andra barn har samma pappa som det första.
Jämför förändringar i fertilitetsutfall hos individer i komunerna som har antagit policyn mot individer i non-reform kommuner.
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Vilka huvudförklaringar finns det till att kvinnor med barn tjärnar mindre än kvinnor utan barn? Hur forskar man på det?
- Att skaffa barn har en kausal effekt på labor market outcomers (man jobbar mindre osv)
- Negativ selektion. Kvinnor väljer att skaffa barn för att de misstänker att de ändå inte kommer klara sig så bra på arbetsmarknaden. Då fokuserar de i stället på att skaffa barn att ta hand om. De skulle alltså jobba och tjäna mindre även om de inte hade barn.
Forskningen har generellt svårt att separera dessa effekter för att få reda på den kausala effekten.
Det har tidigare vari vanligt att använda twillingar och mixed sibling sex compition som instrument när man försöker studera detta. Detta mäter dock effekten effekten för föräldrar som redan har ett barn. De är mer den intensiva marginalen än den extensiva
Vilken typ av marginal-effekt är det som Lundborg, Plug och Rassussen (2012) studerar i sin artikel med IVF mödrar? Vad är behandlings och kontrollgrupp?
Artikeln använder IV data från Danmark för att försöka studera den kausala effekten av att skaffa barn.
De är intresserade av den extensiva marginalen. De studerar därför kvinnor som inte tidigare har barn och som ska göra IVF för första gången. Instrumentet blir ”kvinnor som får en lyckad IVF vid första försöket (dvs att barnet växer och utvecklas). Kvinnor som misslyckas vid första försökte blir kontrollgruppen så att säga.
Sammanfatta Lundborg, Plug och Rassussen (2012).
They examine the labor market response to having children among women who have no children (yet).
To identify fertility effects measured at the extensive margin, they propose a novel instrumental variable (IV) strategy based on in vitro fertilization (IVF). In particular, they sample childless women who go
through IVF and treat IVF treatment success at the first IVF treatment as a natural experiment, and subsequently compare the working careers of women after a successful first treatment (treatment group) to those of women after a failed first treat-
ment (comparison group).
Since observed working histories of successfully and unsuccessfully treated women are virtually identical before they seek IVF treatment, they believe that IVF treatment success creates exogenous variation in the likelihood of having children and can be used as an instrumental variable to estimate the causal effect of having any children on a wide range of female labor market outcomes.
Their main finding is that women who are successfully treated by IVF earn persistently less because of having children.
They explain the decline in annual earnings by women working less when children are young and getting paid less when children are older.
They explain the decline in hourly earnings, which is often referred to as the motherhood penalty, by women moving to lower-paid jobs that are closer to home.
Equally interesting is their finding that the decline in annual earnings we estimate for having children is far greater than the decline in earnings we get when they estimate the effect of having additional children among women who already have children. To put the findings into context, they also estimate the effect of having more children on earnings using the more commonly used instrumental variable strategy based on twin births.
Vilken är Lundborg, Plug och Rassumussen’s (2017) first stage och reduced form?
Deras First (z->x) är Z en binär variabel = 1 om IVF på första försöket lyckades och x = 1 om barnet föds. Reduced for är få X -> Y där Y = labor market outcomes
Berätta om Lundborg, Plug och Rassmussen’s (2017) estimeringsstrategi.
In order to exploit the IVF process to arrive at the causal link running from fertility to earnings, we need an instrument that somehow captures an exogenous shock in IVF-driven fertility.
First, we know that most women undergo multiple IVF treatments to achieve success. With the number of treatments being endogenous, it does not make much sense to treat the success rate in a sequence of IVF treatments as exogenous. So we focus on first IVF treatments.
Second, we are interested in how women respond to exogenous variation in fertility measured at the extensive margin. So we consider childless women entering their first IVF treatment.
Finally, we want these women to be as similar as can be. So we concentrate on childless women who have successfully reached the fourth stage and had embryos implanted.
The parameter of interest is the second-stage parameter, which captures the causal effect of fertility (measured at the extensive margin) on labor earnings t years after these women entered their first IVF treatment.
Vilka tre conditions måste Lundborg, Plug och Rassumussen’s (2017) instrument tillfredställa?
This parameter is identified if the IVF instrument satisfies the following three conditions:
(i) treatment success is correlated with fertility (relevance);
(ii) treatment success is more or less randomly assigned (independence);
(iii) treatment success exclusively affects labor earnings through its first-stage impact on fertility (exclusion).
Varför är Lundborg, Plug och Rassmussen (2017)intresserade av mer en second stage i sin artikel?
While the fertility effect (second-stage) is the target of estimation, we first examine the effect of IVF treatment success on fertility (first-stage) as well as other outcomes (reduced-form).
We do this for two reasons.
First, the first-stage and reduced-form estimates provide insights into the validity of the IVF instrument.
Second, the reduced-form estimates are, as unsealed versions of the second-stage estimates, informative about the causal consequences of having children. If we find no reduced-form effect, we know that there is no causal relationship between having children and labor earnings either.
Vad säger Grönqvists Cost benifit analys
The results presented in this paper suggest that subsidized oral contraception may be a
fruitful way to reduce abortions and teenage pregnancies. Still, back-of-the-envelope calculations show that the societal costs of the subsidy by far outweigh its benefits.
In this context it is important to bear in mind that this calculation leaves out potentially important benefits linked to the socioeconomic outcomes of the women that were given expanded access to inexpensive contraception.
There may also be unmeasured benefits for the next generation. If parents invest more in better planned children these kids may for instance be less likely to engage in crime (Joyce and Levitt 2003) and better off in terms of school performance.
Another issue is that is difficult to estimate the monetary value that both women and men assign to using the birth control pill in relation to alternative contraceptive technologies. If individuals place a high value oral contraception then ignoring this will understate the social benefits.
There are also potential costs not included in this analysis.
One cost could be an increased prevalence of sexual transmitted diseases.
Still, the main lesson from the cost-benefit analysis is that any benefits need to be substantial in order for the subsidy to be cost-effective.” Från Grönqvist
