“…The seminal paper by Brennan und Schwartz (1985) identified the beginning of the practical implementation of RO valuation techniques to projects characterized by high uncertainty, long time horizons, and staging of decisions, such as mining investments. Formal valuation techniques are not always applicable to investment projects, especially when the value of operating flexibility and strategic adaptability cannot be quantified, which is typically the case with R&D projects, investments in new technologies, and innovation portfolios (Gunter McGrath and Nerkar, 2004;Kaufmann al., 2021;McGrath, 1997;Özdemir and van den Ende, 2021). Thus, scholars distinguish between the RO valuation, which applies formal models to estimate RO value, and RO reasoning, which identifies RO value conceptually, applying logic and heuristics (Trigeorgis & Reuer, 2017).…”