"With our own Scottish Chambers of Commerce Quarterly Business Survey projecting only a marginal improvement in output and confidence in the early part of 2013, these latest figures underline the picture of an economy that has been treading water for an extended period of time, " she said.

BBC: Scotland business

At some level of output their marginal costs rise as they begin paying overtime or putting their less efficient facilities into production.

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Platinum is likely approaching the so-called marginal cost of production, which can trigger output cuts in any commodity, said David Wilson, director of metals research at Societe Generale.

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As was demonstrated in the 1970s, even small increases in marginal tax rates have a substantial negative impact on output.

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Growth of output in the manufacturing sector was only moderate, while a marginal rise in new orders offset the fall in new business reported by the service sector.

BBC: Scottish business going through soft patch, says survey