The true value of the 12 days of Christmas reveals giving cash may be the most cost-effective gift

I know what you're thinking: shouldn't economists love Christmas? Isn't Christmas a massive boost to the retail economy? Doesn't it boost spending and create jobs?

Well, in a sense, yes.

Retail sales surge in December. The crucial Christmas and New Year's sales period can make up half of a retailer's profit for the year.

But what really matters to economists is not just that you spend money, but that you get something you really want for it.

In a famous paper titled "Scroogenomics", economist Joel Waldfogel first explained the "deadweight loss" of Christmas.

An economics professor at the University of Pennsylvania, Waldfogel ran a series of experiments with students asking them to assign a dollar value to gifts they had been given.

A consistent gap was found between the dollar value the purchaser paid for the gift and the dollar value perceived by the gift recipient. This gap could be as large as a third of the purchase price, and at least 10 per cent.

This gap - money spent but not enjoyed - represents a deadweight loss to the economy. The gift giver could have spent less to achieve the same result. And the gift receiver could have bought more of what they'd really like for the amount spent.

Apply this gap to the total value of all Christmas spending, and you soon get billions of dollars of deadweight loss.

The answer, according to economists, is simple. Give only one type of gift this Christmas: the gift of cash. And economists wonder why they're not very popular people …!

That said, economists are strangely obsessed with Christmas.

LINK: Full results and cool infographics about the cost of the 12 days of Christmas here: www.pncchristmaspriceindex.com

Economists at the PNC Financial Services Group in the US have been compiling an annual survey of the Price Of Christmas for three decades now.

The 2013 results are in.

The 12 Days of Christmas will set you back $27,393 this year (in US dollars) - up from $25,431 the previous year and from $12,674 three decades ago.

Seven swans a swimming remain the most expensive component of the 12 Days for any "true love" looking to fork out the full carol this year.

According to the survey, and using data from the National Aviary in Pittsburgh, each swan-a-swimming will set you back $1,000.

A partridge, as it turns out, is the cheapest bird of the lot, at $15 each. But you must add $184 for the pear tree, according to information supplied by a plant nursery in New Jersey.

Of the remaining feathers friends, each geese-a-laying will cost you $35 (why not buy six?) followed by $55 for each French hen, $62 for a turtle dove and $150 per calling bird.

As for the humans, there is a vast chasm between wages. It being technically illegal to buy a human, the survey assesses the cost of one hour of labour from the various trades.

Maids-a-milking, deemed unskilled labour, are the cheapest of the bunch. Assuming they receive only the minimum wage in the US - which has not risen since 2009 - each maid will only cost you $7.25 an hour.

In stark contrast, humans employed in the creative industries, of music and performance art, can command much more for an hour of their time.

Each lady dancing will cost you about $840 an hour, according to data supplied by PHILADANCO, a modern dance company in Philadelphia. Lords-a-leaping are cheaper, at $525 an hour, according to the Pennsylvania Ballet.

Pipers piping and drummers drumming are roughly equal in cost at $240 an hour each, according to the Pennsylvania musicians union.

Bag yourself five golden rings for $150 each and you're on your way to true love.

Or, if you're a real economist, just give them $27,393 cash and be on your way.

Happy Christmas everyone.