Proxies for technological change in an economy? I am writing a paper on the application of Value-Added TFP to measurement of technological change. Just thinking of throwing in a few variables into my regression. I have ICT capital share (as seen in KLEMS dataset) as another proxy.

I would be grateful to hear your suggestions on other known proxies (if you know papers that relate to those proxies even better).
I would say these are some proxies


Number of patents
Number of published scientific papers
Human capital