We would like you to assess the QUALITY of each of the following argument (discussing Death Penalty) and determine if the argument is Valid or Invalid. A valid argument is clearly interpretable and either expresses an argument, or a premise or a conclusion that can be used in an argument for the topic of death penalty. An invalid argument is a phrase that cannot be interpreted as an argument or not on the topic of death penalty.

Having catastrophic emotional and physical effects, long and short term.
Invalid

Execution is quick, relatively simple, and very inexpensive regardless of the method used.
Valid

In reality, prison population is a zero sum game because nobody wants a new prison in their back yard (NIMBY principle).

Valid