Similarly, the impacts of transport investments are not always clear. A meta-analysis of 776 estimates of elasticity of production with respect to transport infrastructure finds that the estimated effect of investing in transport infrastructure varies from -0.06 to 0.52, with the effect depending on the type of infrastructure and the economic sectors (Holmgren & Merkel, 2017). Investments in air transport seem to have the highest impact for the agricultural and service sector, road investments on production in construction and manufacturing and port infrastructure on the agricultural sector. Roberts, Melecky, Bougna, & Xu (2018) review the impacts of investments in transport corridors on welfare, social inclusion, equity, and the environment across 78 papers and find that transport investments always have a positive impact on real income and poverty. However, some have negative impacts on equality (with regions winning and others losing from the investments) including sometimes absolute negative impacts on some groups.

Two possible explanations may account for these varied findings. First, it may be that access to infrastructure is not necessarily a priority for extremely poor households who may face other binding constraints, cannot afford appliances or machinery, have limited access to market centers, and may struggle to cover the cost (even subsidized) of electricity, water or transport. There is evidence in a variety of places that poorer households either have no service or have illegal connections –with no or low payments–. When there is infrastructure development, they cannot afford the price of the connection or the fees and experience a ‘worst’ service than before. Infrastructure development also induce a greater control over the networks and the invoicing/consumption which tightens further the issues. Second, it may be that expansion of infrastructure in some countries has come at the cost of unreliable service: increasing investments in new infrastructure contributes to stretching resources for operations and maintenance and tends to increase the networks vulnerability.

Indeed, being connected to infrastructure is not enough: the quality of the service and its reliability also matters, and the lack of reliability can affect households through many channels. There are several channels through which infrastructure service disruptions affect households (Table 1). Some channels are linked to each individual disruption and include the direct short-term consequence of not having access to electricity, safe water, transport, or communication. For instance, activities affected by power outages include cooling and heating (and health implications), economic activities and income, studying of children and education outcomes, social and leisure activities, and regular household tasks such as cooking and cleaning (Pasha & Saleem, 2013). But some effects may materialize only over the long term, and as a result of the repetition of outages, such as the decision not to invest in food refrigeration or air conditioning due to lack of power reliability. In those cases, each individual outage does not have a cost associated to it anymore, since households give up on some types of energy use. Finally, in addition to the impact of outages, households incur additional costs linked to investments to mitigate the impact of outages. Selfgeneration for electricity, water reservoirs for water supply, or the ownership of a vehicle to compensate for inadequate public transit can be extremely costly for households.

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