Thursday, April 01, 2010

EKOS President Frank Graves' Funny Math

Somehow for journalist Bill Curry and EKOS President Frank Graves, a drop of 1.1% for Conservatives is smaller than a drop of .7% for Liberals.

With the release of a new poll from EKOS, a new round of commentary begins, and though it can be safely concluded most of it is highly suspect, it can be rarely proved wrong, Bill Curry and Frank Graves however offer an exception.

Bill Curry has written an article for the Globe and Mail titled, "Tories slip, but Liberals slide further in latest poll," and though from reading the headline most would assume the Liberals fell by a larger margin than Conservatives, they would be wrong. The EKOS poll reports Liberal support declined from 27.7% to 27%, for a drop of .7% over a one week period, while the Conservatives declined from 33.3% to 32.2% for a 1.1% drop. Apparently for Bill Curry, .7 is larger than 1.1.

Bill Curry might be excused as he could be seen as trying to report the expert conclusions of EKOS President Frank Graves who said:

“The leading indicator of confidence in the federal government is down significantly this week, which is not a good harbinger of the future; yet it is even a worse poll for the Liberals who are now down firmly in Dion territory, despite the weekend think fest.”
Though Frank Graves's offers no mathematical explanation of how .7% is larger than 1.1%, his lapse in statistical judgement could be defended by the claim he meant it was worse for the Liberals as they are now at record low levels. This suggestion however is ultimately groundless, for if these rates of decline continued for both parties, even though the Liberals' drop is supposedly worse than the Conservatives', in less than 12 weeks the Liberals would be ahead. This extrapolation is of course flawed, but it only goes to illustrate that so too is Frank Graves analysis, his just happens to be more obvious.


Doyen said...

The reason for the context of the Liberals 'sliding further' is since the Liberals have dropped in the (Ekos) polls for the fourth straight week. March 11 was 29.6%, March 18 was 28.9%, March 25 was 27.7% and April 1 was 27%.

Alternately, while the Tories slipped to 32.2% from last week's result of 33.3%, the week *prior* to that they were 31.1%, so they *gained* ground a week ago.

IOW, the 'slide' is a reference to the continued drop of the Liberal party over the last four weeks, while the Tories have not had the same week over week drop. said...

Doyen that's a probable explanation, My problem would be there was no reference to that in the article.