With the Digital Markets Act, regulators in Europe are going after big platforms for self-preferencing. The Act forbids "gatekeeper" platforms from ranking their own products more favorably. Is regulation affecting Amazon's behavior? 1/n
nber.org/papers/w32299 Documenting self-preferencing is hard because it’s not clear how highly Amazon’s own products should be rated. Perhaps consumers like Amazon Basics products and prices, and the products should receive favorable rankings. 2/n

Regulators are banning platform self-preferencing (e.g., Amazon favoring its products in search results). But what does that even mean? In a new working paper, @ReimersImke and I offer a simple framework to both test for platform bias and measure its welfare consequences. 1/n Here’s the setup. Platforms rank products – in search results and on product pages – and these rankings affect purchase behavior. The rankings could serve the interests of sellers, buyers, or – if the platform benefits more from selling its own products – the platform itself. 2/n

Colleagues and I have a new paper on GDPR whose abstract has prompted a little Twitter heat. I’ll add my perspective, consisting mostly of cool water. 1/n
@JanssenReb @reinholdkesler Michael Kummer
nber.org/papers/w30028 GDPR aims to improve privacy in various ways, some of which are costly to app developers. As a result, GDPR induced a large number of apps to exit rather than face the costs of coming into compliance.

Powerful platforms – and the possibility of bias - are on everyone’s mind these days. For example, Google got in hot water for favoring its own properties in search. How about bias at Spotify? 1/n I explore this in a new paper with @luisaguiarw and @swald709 nber.org/papers/w29017

It's well-known that covid-19 has caused streaming video use to skyrocket. This is understandable: People have time on their hands, and they can use a diversion.
cnn.com/2020/03/19/tec… What about music listening? Research documents that music reduces stress, and maybe we should expect music listening to rise in hard-hit countries. blogs.psychcentral.com/nlp/2015/04/5-…

@ReimersImke and I are happy to share a new working paper comparing the welfare benefit of traditional vs digital sources of pre-purchase information.
1/n The backdrop: Digitization has delivered tons of beneficial new creative products. Pre-purchase guidance, traditionally from professional reviewers, is useful with these experience goods. But the flood of new products strains reviewers’ capacity.
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Here's a thread about my new paper asking how the inclusion of cuisine affects global patterns of cultural trade. Answer: a lot.
1/7 The US is viewed as a cultural imperialist, particular by European regulators, who protect and subsidize their domestic music and movie industries. Regulators’ fears have some basis in reality, as Hollywood accounts for the vast majority of world movie revenue.
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