Obviously some are, some aren't. It depends heavily on how those four days are managed, the nature of what you specifically need to be doing while "on duty", e

Obviously some are, some aren't. It depends heavily on how those four days are managed, the nature of what you specifically need to be doing while "on duty", etc. Reasonable companies will recognize that an efficient 32 hours can be as productive (or more so) than an inefficient 40 hours. The trick is to show that this is the reality of what happens. If you can generate empirical evidence supporting the same, it should be an easy sell. Good defect and task tracking can help with this.