OTTAWA -- Canada's official unemployment rate is among the most watched economic indicators by markets and policy-makers, but it may be overestimating the actual health of the country's labour market, according to the Bank of Canada.

The central bank says in a new research paper that unemployment rates have "overstated" the jobs recovery in Canada and particularly in the U.S. because they fail to capture a complete picture of what is happening in the labour market.

In the paper, the bank creates a composite labour market indicator, or LMI, that combines a broad range of measures to paint what it says is a more accurate picture of what has occurred since the 2008-09 recession.

The LMI, which includes less publicized indicators such as hours worked, wage growth, long-time unemployment, labour underutilization and other data points, resolves one of the puzzles of current statistics that has the U.S. unemployment rate at 6.3 per cent, well below Canada's 6.9 per cent, even though by all other measures the U.S. labour market is far weaker.

But it also shows Canada's jobs recovery, while stronger than in its southern neighbour, has not been as strong as the unemployment rate would suggest.

Between 2010 and 2013, the bank says Canada's jobless rate fell 0.9 percentage points. But the LMI fell only 0.5 percentage points in the same period, suggesting more softness in the labour market than reflected in the official unemployment rate.

"Although the unemployment rate in Canada has evolved largely in line with overall labour market conditions since the recession, the article has shown that it may have modestly overstated the extent of recent improvement," the research paper notes.

"This article highlights the need to consider a broad range of labour market variables in addition to the unemployment rate."

The paper was one of five issued by the central bank Tuesday on the economy and financial markets, including reports on the increasing use of the loonie as a global reserve currency and on digital currencies.

Canada's impressive job creation record since the recession has been a key talking point among Conservative government ministers to back their economic management, including until recently, support for importing temporary foreign workers to meet labour shortages.

But there has also been discordant voices, including from the Parliamentary Budget Officer, that suggest labour shortages have been exaggerated. Recently, the government radically revised downward it's estimate of job vacancies by dropping job postings from Kijiji after the PBO called the data unreliable.

Employment Minister Jason Kenney suggested this week in the House of Commons that there are no postings listed on the federal government's controversial job bank website that are older than six months. He said the normal maximum posting period is 30 days, even though - when checked - many of the jobs listed on the job bank are no longer available.

The new Bank of Canada research suggests that while by some measures Canada's labour market has recovered, by others there's still a long way to go.

"The percentage of unemployed workers who are considered long-term unemployed ... peaking at just over 20 per cent in June 2011 ... has not shown much improvement. . ." the bank notes. As well, "job-finding rates," after an initial improvement following the slump, have "since fallen back to a level only slightly above the low point witnessed during the recession."

In other research paper, the bank notes that the loonie has gained in prominence as a global reserve currency since the recession.

It calculates foreign governments now hold about US$200 billion in Canadian currency, almost twice the IMF estimate, or about 1.8 per cent of the total world reserve holdings.

The global confidence in the loonie, which is backed by relatively low levels of government debt, has resulted in lower bond yields and reduced Ottawa's interest payments more than otherwise would have been the case. But increasing use of the loonie as a reserve currency can also reduce market liquidity, the bank says, which can also cause bond yields to rise.

The bank also examined the growth of so-called digital currencies, such as the Bitcoin and Amazon coins, concluding that while they have the potential to challenge more traditional currencies, none is widely used at the moment.