Newspapers - report elections or sway elections?

"It was the Sun what won it" is an apochryphal newspaper headline from an election gone by. Today's Guardian carries a piece about tactical voting, urging readers to be sceptical about the extent that newspapers can influence their audience.

"Whenever tactical voting is mentioned, someone usually mentions the Observer polls of marginal seats in 1997, which are credited with helping to defeat a string of Conservative MPs, including Michael Portillo.

It was, it claimed, "the Obs what won it". Yet there is almost no evidence that these polls had any influence on the result.

The polls showed the Tories in deep trouble and heading for a string of defeats, and four days later, hey presto, that's what happened.

The Observer observed - it did not influence."

Some might say - the difference between enumerative and analytic studies.