L. Rachel Ngai




Associate Professor, London School of Economics

Research Fellow, CEPR.

Member, CFM



Department of Economics, LSE, Houghton Street, London WC2A 2AE, UK

Email: L.Ngai"at"lse.ac.uk

Phone: +44 2079557017

Working Papers

·      Structural Transformation over 150 Years of Women's and Men's Work (with Claudia Olivetti and Barbara Petrongolo), October 2022.

Abstract: We build a consistent measure of male and female work for the US for the period 1880-2019 - encompassing intensive and extensive margins - by combining data from the US Census and several early sources. The resulting measure of hours, including paid work as well as unpaid work in family businesses, displays an asymmetric U-shape for women, with a modest decline up to mid-20th century and a sustained rise afterwards. For men, hours fall throughout the sample period. We empirically and theoretically relate these trends to the process of structural transformation, and namely the reallocation of labour across agriculture, manufacturing and services, and the marketization of home production. We propose a multisector model of the economy with uneven productivity growth, income e ects, and consumption complementarity across sectoral outputs. At early stages of development, declining agriculture leads to rising services (both in the market and the home) and leisure, implying a fall in market work for both genders. At later stages of development, structural transformation reallocates labor from manufacturing into services, and a large service economy implies an important marketization process, progressively reallocating work from home to market services. Given gender comparative advantages, the first channel is more relevant for men, implying a decrease in male hours, and the second channel is more relevant for women, implying an increase in female hours.

·      Ins and Outs of Selling Houses: Understanding Housing-Market Volatility  (with Kevin Sheedy), August 2022. CFM-DP2022-13


        Previous version, January 2020. CEPR DP 14331

Abstract: The housing market is subject to search frictions in buying and selling houses. This paper documents the role of inflows (new listings) and outflows (sales) in explaining the volatility and co-movement of housing-market variables. An ‘ins versus outs’ decomposition shows that both inflows and outflows are quantitatively important in understanding fluctuations in houses for sale. The correlations between sales, prices, new listings, and time-to-sell are shown to be stable over time, while their correlations with houses for sale are found to be time varying. Using a housing-market model with endogenous inflows and outflows, a single persistent housingdemand shock can explain all the patterns of co-movement among variables except for houses for sale. Consistent with the data, the model does not predict there is an invariant structural relationship between houses for sale and other variables—the correlation depends on the source and persistence of shocks.


·      To Own or to Rent? The Effects of Transaction Taxes on Housing Markets (with Lu Han and Kevin Sheedy), July 2022.  CEPR DP17520

Abstract: Using sales and leasing data, this paper finds three novel effects of a higher property transaction tax: higher buy-to-rent transactions alongside lower buy-to-own transactions, despite both being taxed; lower sales-to-leases and price-to-rent ratios; and longer time-on-the-market. This paper explains these facts by developing a search model with entry of investors and households who decide to own or rent. The transaction tax increases the demand for rental properties, which reduces the homeownership rate and homeowners’ mobility. The deadweight loss from the tax is large at 79% of revenue, with 40% of this due to the decision to own or to rent.

·      A Multisector Perspective on Wage Stagnation  (with Orhun Sevinc), February 2022. (Listen to the main idea on Vox Talks). CEPR DP 14855

A nice video on the main idea of the paper produced by the LSE Research.


Abstract: Low-skill workers are concentrated in sectors that experience fast productivity growth and yet their wages have been stagnating. We document evidence from U.S. to show the importance of a multisector perspective. Key to our mechanism is the fall in the relative price of the low-skill sector caused by faster productivity growth. When outputs are complements across sectors, this leads to a reallocation of low-skill workers into the high-skill sector where their marginal product of labor is stagnant. We show this mechanism is quantitatively important for the low-skill wage stagnation and
its divergence from the aggregate labor productivity during 1980-2010.



·      Taxes, Subsidies and Gender Gaps in Hours and Wages (with Robert Duval-Hernandez and Lei Fang), forthcoming, Economica.


        Online Appendix -- Proofs and calibration procedures


        Previous versions: CEPR DP12292. CFM 2018-04 (VoxEU Column). SOEP paper No 962 


Abstract: Using micro data from 17 OECD countries, this paper documents a negative cross-country correlation between gender gaps in market hours and wages. We find that the cross-country differences in market hours are mostly accounted for by female market hours and the size of the sector that produces close substitutes to home production. We quantify the role played by taxes and family care subsidies on the two gender gaps in a multi-sector model with home production. Higher taxes and lower subsidies reduce the marketization of home production, leading to lower market hours. The effect is largely on women because both home production and the production of its market substitutes are female-intensive. The larger fall in female market hours reduces relative female labor supply, contributing to a higher female to male wage ratio.



·      Time Use and Gender in Africa in Times of Structural Transformation (with Taryn Dinkelman), Journal of Economic Perspective Winter 2022, 36(1): 57-80.  (VoxEU Column)


        Video interview by CEPR VoxEU.

Abstract: Many African countries are still in the early stages of structural transformation. Typically, as economies move through the structural transformation, activities once conducted within the household are outsourced to the market. This has particular implications for women’s time use. In this paper, we document that current patterns of female time use in home production in several African countries closely resemble historical time use patterns in the US. We highlight two stylized facts about women’s time use in Africa. First, in North Africa, women spend very few hours in market work and female labor force participation overall is extremely low. Second, although extensive margin participation of women is high in sub-Saharan Africa, women tend to work in the market for only a few hours each week, with the rest of their work hours spent in home production. These two facts suggest two types of constraints that could slow down the reallocation of female time from home to market as economies grow: Social norms related to women’s market work, and a lack of infrastructure (e.g. household infrastructure and childcare facilities) to facilitate marketizing home production. We discuss recent empirical evidence related to each set of constraints and highlight new avenues for research.


·      Rising inequality and trends in leisure (with Timo Boppart). Journal of Economic Growth June 2021, 26(2): 153-185.


Keywords: Trends in leisure, inequality, balance growth path.


·      Home Production, Women's Market Work and Structural Transformation (Taryn Dinkelman), April 2021. Structural Transformation and Economic Growth STEG Pathfinding Paper.

Keywords: Female time allocation, home production, structural transformation.


·      The decision to move house and aggregate housing-market dynamics (with Kevin Sheedy). Journal of the European Economic Association, Oct 2020, 18(5): 2487-2531.  (VoxEU Column )


Previous title "Moving House". CEPR DP10346. CFM 2016-21

Keywords: search and matching, endogenous moving, match quality investment, mismatch


·      China's mobility barriers and employment allocations (with Chris Pissarides and Jin Wang). Journal of the European Economic Association, Oct 2019, 17(5): 1617-53.  (VoxChina Column)


       Keywords: Mobility barriers, China's Hukou system, land policy, location-based social subsidies, structural transformation, urbanization



·      Gender Gaps and the Rise of the Service Economy (with Barbara Petrongolo). American Economic Journal -- Macroeconomics, October 2017, 9(4): 1-44.


        2018 AEJ: Macroeconomics Best Paper Award


        A nice video on the main idea of the paper produced by the American Economic Association.


       Previous title "Structural Transformation, Marketization and Female Employment".  CEP DP1204.  CEPR DP 9970.

Keywords: gender gaps, structural transformation, home production, rise in female market hours, fall in male market hours, rise in gender wage ratio


·          Hot and Cold Seasons in the Housing Market (with Silvana Tenreyro). (Web Appendix), American Economic Review, December 2014, 104(12): 3991-4026.

Keywords: seasonality, the U.K. and the U.S. housing markets, match-specific quality, thick-market effect.

·      Taxes, Social Subsidies and the Allocation of Work Time  (with Chris Pissarides), American Economic Journal - Macroeconomics, October 2011, 3(4): 1-26.

   Previous title: "Welfare Policy and the Sectoral Distribution of hours of Work".

Keywords: time allocation, home production, welfare policy (taxes and subsidies), 19 OECD countries


·        Accounting for Research and Productivity Growth Across Industries (with Roberto Samaniego), Review of Economic Dynamics, July 2011, Volume 14, p. 475-495.        

Keywords: cross-industry productivity growth, endogenous growth model, R&D.


·        Mapping Prices into Productivity in Multisector Growth Models (with Roberto Samaniego), Journal of Economic Growth, September 2009, Volume 14, p.183-204.    

Keywords: input-output table, intermediate goods, investment-specific technical change (ISTC).


·        Trends in Hours and Economic Growth (with Chris Pissarides), Review of Economic Dynamics, April 2008, Volume 11, p. 239-256. 

Previous Title: "Trends in Labour Supply and Economic Growth"

Keywords: structural transformation, marketization, home production, trends in aggregate market hours, aggregate balanced growth path.


·        Employment outcomes in the welfare state (with Chris Pissarides), Revue economique 2008, 59(3) p413-436. 

Keywords: marketization, home production, social subsidies and taxes.


·         Public Enterprises and Labour Market Performance (with Johannes Hörner and Claudia Olivetti), International Economic Review, May 2007, Volume 48, No. 2, p. 363-384.

Keywords: Unemployment, public sector employment, economic turbulence


·         Structural Change in a Multisector Model of Growth (with Chris Pissarides), American Economic Review, March 2007, Volume 97, No. 1, p. 429-443.

A longer working paper version: CEPR DP 4763. Previous title: "Balanced Growth with Structural Change".

Keywords: multi-sector growth model, structural change (Kuznets' facts), aggregate balanced growth path (Kaldor's facts)  


·         Barriers and the Transition to Modern Growth, Journal of Monetary Economics, October 2004, Volume 51, Issue 7, p. 1353-1383.

Keywords: cross-country income differences, stagnation to growth, transitional dynamics.


Last update: January 2023