Historically there was and in some countries still is much debate about the best level for interconnection rates. Some argue that approaches based on models do not take into account real world risks and costs and suffer, among other things, from survivorship bias (they consider that risk can be assessed by looking only at the returns of surviving companies) and therefore underestimate the true level of risk. Another concern is based on Real Options. This considers the benefit that is extinguished from the moment that an investor chooses to invest and suggests that the loss of this right to invest should be taken into account when looking at the expected returns on investments made.