Are we measuring child poverty accurately?

Controversial Cabinet Minister Iain Duncan Smith is proposing new ways of measuring child poverty. It's the latest row involving the man bringing us a massive welfare shake-up. Mr Duncan Smith wants a new child poverty measurement system that's not just based on family income. He thinks it should cover the likes of marriage stability, having parents in employment, and going to good schools. Does the current measurement accurately show the number of children living in poverty here?