"In this respect a program is like a poem: you cannot write a poem without writing it. Yet people talk about programming as if it were a production process and measure 'programmer productivity' in terms of 'number of lines of code produced'. In so doing they book that number on the wrong side of the ledger: We should always refer to 'the number of lines of code spent'."
Or, if you prefer Dijkstra:
"In this respect a program is like a poem: you cannot write a poem without writing it. Yet people talk about programming as if it were a production process and measure 'programmer productivity' in terms of 'number of lines of code produced'. In so doing they book that number on the wrong side of the ledger: We should always refer to 'the number of lines of code spent'."