While in CS multi-author papers are the norm, in econ it is quite common to have solo-authored papers, with senior PhD students solo-authoring papers without their advisor as a coauthor. And it is rare to see an econ paper with more than 3 authors.
As a CS PhD who has worked with many economists, my understanding is that the culture sees it as diluting credit, and so might put people in the acknowledgements where computer science folks would add them as authors.
As a CS PhD who has worked with many economists, my understanding is that the culture sees it as diluting credit, and so might put people in the acknowledgements where computer science folks would add them as authors.