Effective slides should be standalone documents that can be read on their own,without a presenter.

Another reason for ineffective slides is the practice of treating slide sets as standalone documents that can be read on their own, without a presenter. (The emergence of websites such as SlideShare might be contributing to this, too, by making it so easy to share slide sets.)These "slideument" hybrids that try to function as both presentation visuals and printed documents don't work well as either.