Distinguishing correlation and causation is the constant challenge and peril of all social science research, where mechanisms are complex and measurements indirect. There are a few methods which do offer some insight, the two most effective I'm aware of being identical-twin studies and qualification-test cut-off divisions.

In twin studies, the goal is to study twins (identical genetic inheritence) either from the same household (similar socioeconomic environment) or separate ones (often foster-parent settings or other forms of adoption), and comparing life trajectories, educational attainment, and employment history. I'm not specifically aware of education-related studies of this form, though I'd strongly recommend literature search (Google Scholar, etc.) on keywords such as "twin studies education".

On test-cutoff studies, there was one I ran across recently in which individuals who tested just at the cutoff of the qualification threshold for advanced academy entrance. That is, students scoring above the threshold attended the schools, those below did not. The findings were of comparable subsequent lifetime attainments (employment, income), suggesting that innate ability was a stronger predictor than educational history. I can't find the study presently, though I'm pretty certain it addressed the Specialised High Schools Admission Test (SHSAT):

https://en.wikipedia.org/wiki/Specialized_High_Schools_Admis...

Far more studies look at basic demographic or geographic data. To a large extent this constitutes an availability heuristic: the data are far more abundant and more readily available. How predictive they are on a causality basis is harder to determine. One example (turned up whilst searching for the entrance-exam study):

"Money, Race and Success: How Your School District Compares" (2016)
https://www.nytimes.com/interactive/2016/04/29/upshot/money-...

Another school of thought (so to speak) is on what education's impact socially is, at least along economic-performance measures. (There are of course other legitimate outcomes of education, including its roles in culture and democratic institutions.) Such viewpoints often come from the right, though may also be found among more liberal economists. One such, Ha-Joon Chang addresses this in chapter 17 of 23 Things They Don't Tell You About Capitalism, "More education itself is not going to make a country richer" (2010). Dr. Ha-Joon notes that:

1. Many poor countries have high educational attainment.

2. Many rich countries have comparatively low attainment.

3. Numerous countries (particularly in east / southeast Asia) have made remarkable economic progress without especially high educational attainment.

4. Mechanisation has a far greater impact on per-worker productivity than education.

5. Businesses generally prefer de-skilling work in order to make labour more substitutable. This of course reduces the benefits of education.

Additional points (Ha-Joon does not address these directly) are that infrastructure counts for a great deal, and "brain drain" --- economic migration by the more educated --- can siphon off a country's most educated citizens, essentially subsidising the economies of other countries.

See: https://www.worldcat.org/title/twenty-three-things-they-dont...

Among Ha-Joon's more interesting citations:

L. Pritchett, "Where has all the education gone?", The World Bank Economic Review, 2001, vol. 13, no. 3. https://documents.worldbank.org/curated/en/85982146818027378... (PDF)

Harry Braverman, Labor and Monopoly Capital: The Degradation of Work in the Twentieth Century (1974) https://nyupress.org/9780853459408/labor-and-monopoly-capita...

Stephen Marglin, "What do Bosses Do?", published in two parts in The Review of Radical Political Economy, 1974, 1975. https://scholar.harvard.edu/marglin/publications/what-do-bos... https://scholar.harvard.edu/marglin/publications/what-do-bos...