It has to do with the relative weight given to various factors. I can't speak for private sector economists or the Bank of Canada.
As for our office, we expect business investment to pick up during the second half of 2019, with energy prices and the curtailment of Alberta oil production favouring investment and economic recovery. We also expect interest rates to remain relatively stable until the end of 2019. In addition, the labour market should remain fairly strong across the country, nationally speaking. Given all those considerations, our projections are likely to be a bit more optimistic than others.
Some uncertainty does, however, persist, particularly on the international trade front. Therefore, our projections are probably not as optimistic as others in that regard.