Economist Bias

Economists have to an increasing extent tended to over-estimate the monthly inflation-rate in Sweden. Are they using an old map that lacks e.g. the recent trend towards inexpensiveness, "billighetstrenden" in retail? Here is what one analyst wrote yesterday a propos the soon to be announced Swedish February CPI:

The February CPI figure, due Friday, is expected to print 0.1% according to economists polled by Bloomberg, 0,2% says Sweden-based pollster SME-Direkt. ... For a quantitative perspective, economists have on average overestimated inflation by 0.05% since Oct 02. During last year, they overestimated inflation in most months, on average the figure came out 0.1% below expectations. The very last number, the Jan CPI came out -0.5% and was estimated -0.2% in Bloomberg’s poll