The probability of alien species invasion is reasonably characterized by a weakest link technology. A tradeable risk permit system for shippers has been proposed as a means of efficiently reducing this invasion probability. Economic jointness arising from statistical independence among private...

Protection against pest invasion is a public good. Yet the nature of private incentives to avoid entry is poorly understood. This work shows that, due to increasing returns or network effects, private actions to avoid entry are strategic complements. This means that compulsory action, at least...