Adverse health shocks fuel discontent. Social unrest can be driven by grievances with the provision of local public services. This column examines the effect of a large-scale health intervention – the expansion of HIV antiretroviral therapy – on violent events throughout Africa. Where the treatment was expanded, incidents of social violence dropped substantially at both country and sub-national levels. This finding shows that successful public health interventions can yield legitimacy to the state, help build trust, and serve as a ‘medicine’ against both ill health and conflict.

Historical institutions can have long-lasting effects on societies and economies. The Inca Road has been a linchpin of the colonial economy in the New World, but its impact on current development has not been studied in great depth. This column examines the impact of the road on today’s educational, development, and labour outcomes. Proximity to the Inca Road increased the average level of educational attainment and decreased stunting among children by 5%. It boosted average hourly wages by 20% and reduced informality by six percentage points. Moreover, these effects were around 40% greater among women.

Affirmative action policies are widely used to tackle the underrepresentation of certain groups. However, the efficiency of these policies is fiercely debated. This column uses novel data from India to explore how affirmative action quotas affect everyday discrimination. Local political council quotas for marginalised castes are found to reduce caste-based discrimination by around one fifth, but the effect disappears when the quotas are removed.

Although spatial differences in economic development tend to be highly persistent over time, this is not always the case. This column combines novel data on Roman Empire road networks with data on night-time light intensity to explore the persistence and non-persistence of a key proximate source of growth – public goods provision. Several empirical strategies all point to the Roman road network as playing an important role in the persistence of subsequent development.

Throughout history, most states have functioned as kleptocracies and not as providers of public goods. This column analyses the diffusion of legal institutions that established Europe’s first large-scale experiments in mass public education. These institutions originated in Germany during the Protestant Reformation due to popular political mobilisation, but only in around half of Protestant cities. Cities that formalised these institutions grew faster over the next 200 years, both by attracting and by producing more highly skilled residents.

With governments strapped for cash, charities are stepping up to provide public goods. But how can charities mobilise support from small donors to fund their work? CEPR DP8922 investigates whether altruists would donate more if they knew more about a charity’s quality. In the authors’ experiment, Bill and Melinda Gates matched donations to a particular charity. Small donors saw this as a signal of the charity’s quality – and donations soared.

Ethnically diverse groups are less successful in providing public goods. This column suggests that affective interpersonal relationships may be a critical component in cooperative behaviour and outlines the evidence – from brain scans to experimental games – of their importance.