|**Table 8: Returns to cognitive and soc**|**ial-emotional s**<br>Ttl t|**kills from**|**low- an**|**d middle**|**-income**|**studies**||Lbd|Upper-bound|
|---|---|---|---|---|---|---|---|---|---|
||oa coss<br>per child<br>(dollars)|Preprim|ary-augm|entation t|o lifetime|earnings (|dollars)|ower-oun<br>benefit-to-cost<br>ratio|<br>benefit-to-cost<br>ratio|
||(1)|(2)|(3)|(4)|(5)|(6)|(7)|(8)|(9)|
|**Panel A:**Discount rate = 3%||||||||||
|India (Ganimian et al, 2021)||||||||11.1|11.8|
|India (Dillon et al, 2017)|$53|$913|$2,845|$1,429|$302|$2,234|$817|5.7|54.0|
|Malawi (Ozler et al, 2018)|$72|$782|$2,010|$1,109|$259|$1,487|$586|3.6|28.1|
|Ghana (Wolf et al, 2019a)|$16|$563|$1,657|$855|$186|$1,280|$478|11.6|103.5|
|Peru (Gallego et al, 2021)|$37|$3,264|||$1,080|||29.2|88.2|
|Bangladesh(Spier et al,2020)|$145|$1,542|$4,175|$2,244|$510|$3,143|$1,212|3.5|28.8|
|**Panel B**: Discount rate = 5%||||||||||
|India (Dillon et al, 2017)|$53|$411|$1,281|$643|$136|$1,006|$368|2.6|24.3|
|Malawi (Ozler et al, 2018)|$72|$370|$950|$524|$122|$703|$277|1.7|13.3|
|Ghana (Wolf et al, 2019a)|$16|$271|$796|$411|$89|$615|$230|5.6|49.7|
|Peru (Gallego et al, 2021)|$37|$1,587|||$525|||14.2|42.9|
|Bangladesh(Spier et al,2020)|$145|$738|$1,999|$1,074|$244|$1,505|$580|1.7|13.8|
|High cognitive wage returns||Yes|Yes|Yes|No|No|No|||
|Low cognitive wage returns||No|No|No|Yes|Yes|Yes|||
|High social-emotional wage returns||No|Yes|No|No|Yes|No|||
|Low social-emotional wage returns||No|No|Yes|No|No|Yes|||

_Notes_ : For each country, we first calculate the present discounted value of a child's lifetime earnings, assuming that the child will work from age 22 to 65. To do this, we use the average nominal monthly wages for the latest year available, as well as the labor force participation rate and the average growth in real wages for the 2015-2019 period. See Appendix Table 4 for these parameters and our sources of data for all studies except for Ganimian et al, (2021), for which we directly use their estimates of benefit to cost ratios. In Panel A, when discounting future earnings to the present value, we assume a discount rate of 3 percent per year. In Panel B, we assume 5 percent per year. To calculate gains to lifetime earnings from preprimary interventions, we use the lowest significant treatment effect on cognitive skills reported in standard deviations in the paper and the lowest significant treatment effect on social-emotional skills. We use high and low estimates from the literature on the returns to a standard deviation increase in cognitive or social-emotional skills. Kline and Walters (2016) use an annual return of 13 percent per standard deviation of cognitive skills, while Galasso and Wagstaff (2018) use 4.3 percent. For the returns to social-emotional skills, Belfield et al (2015) use a range of 4 percent to 15 percent. We vary our assumptions on these returns in Columns 2 through 7. Because papers (with the exception of Ganimian et al., (2021)) reported costs per child in US dollars, we discounted lifetime earnings to the year costs were incurred and used nominal exchange rates collected by the International Monetary Fund to convert earnings to dollars in the year costs were incurred. In Columns 8 and 9, we report the ratio of benefits to costs for an individual child.