The initial hope for climate science was that an improved understanding of what the future might bring would lead to appropriate public policies and effective international climate agreements. Even if that hope is not realized, as now seems likely, scientific advances leading to a more refined...

Strategies selected by combining multiple signals suffer severe overfitting biases, because underlying signals are typically signed such that each predicts positive in-sample returns. “Highly significant” backtested performance is easy to generate by selecting stocks on the basis of...