I want to introduce you to "creaming," "parking" and "gaming." It sounds a bit disgusting - like something the dogging community might get up to in a Ford Mondeo in the New Forest, but actually they are how big firms cheat us out of money.
When the National Audit Office looked at Iain Duncan Smith's "benefit-busting" scheme, called the Work Programme, it got Portsmouth University academic Professor Dan Finn to look at the dangers shown by international versions of this programme.
Duncan Smith's scheme is entirely delivered by private companies. Big firms like A4E or Ingeus run "job club"-type schemes. They get paid bonuses every time an unemployed member of their "club" gets a job.
But Finn examined how contractors can in effect cheat the benefits system. He warned of creaming, parking and gaming.
In his report Finn writes: "'Cream-skimming' occurs when providers select the more job-ready or more motivated participants to help meet targets or gain outcomes instead of selecting those with the potential to gain more in the longer term.
"'Parking' occurs after recruitment when providers may put less effort and investment into working with harder to place participants.
"'Gaming' occurs when providers seek to exploit weaknesses in programme design by undertaking activates which allow better performance on contractual criteria but do not improve employment outcomes. At its most extreme 'gaming' may involve fraudulent activity."
Variations on these problems can occur whenever public services are contracted out.
You get what are called "perverse incentives" - again, it sounds like this is something the New Forest doggers get up to, but it means that companies can make more money by fiddles and tricks than by actually helping the unemployed.
You can get similar problems with health and welfare privatisation. But don't worry, Frances Maude's Cabinet Office is on to the tricks.
It is piloting a new set of welfare services for "problem" families and the unemployed.
These new schemes will be run by private companies and funded by private investors and seek to keep the most troubled people in jobs and out of prison. The taxpayer will then pay them back over years.
These kind of schemes can end up siphoning cash into private investors' and contractors' pockets.
But Maude has hired the top people to design the new schemes. They will be writing a "how to" guide and advising No 10.
According to the contract they will help to avoid dangers like "failing to cash savings, risk of perverse incentives, risk of deadweight, risks of cream-skimming/cherry-picking, risk of outcomes being made worse as a result of the contract, etc."
And who are these experts advising the Cabinet Office? None other than A4E, the firm currently being audited for fraud across all its welfare programmes.
Emma Harrison no longer sits on the board of her own firm. She still owns A4E but has stood back because she was a lightning rod for criticism.
She also deleted her Twitter stream shortly after recommending that everyone read an article calling A4E "the dark side of the Big Society."
The last "tweet" from "Emmachat - Friend, Mum, Entrepreneur" pointed to a Fraser Nelson article in the Telegraph.
Nelson said Harrison's firm could "get things badly wrong" and that the A4E "scandal is still unfolding."
"A4E was being given multimillion-pound contracts and growing at what was probably too fast a rate," Nelson argued.
"It was only a matter of time before something, somewhere, went wrong."
Nelson did say A4E is suffering from "double standards" because fraud and failure happen in the public sector as wall - hardly a stirring defence.
That said, he might have offered Harrison some comfort with his claim that A4E "is a company that matches unemployed British workers with jobs and has grown by being able to do so far better than government agencies."
But this one friendly statement was fact-free. When auditors made the private-public comparison, A4E was found to have "universally failed" to meet targets and "performed worse than Jobcentre Plus."
Shadow chancellor Ed Balls has subcontracted Labour's economic analysis to PriceWaterhouseCoopers - PwC for short - the firm which lumbered the last Labour government with PFI schemes, poor banking supervision and tax avoidance.
In the latest register of MPs' interests Balls announces PwC is giving him "a research assistant/analyst to support me in my opposition front-bench role" from January to April.
Balls says PwC assistance is worth £880 a day.
Labour has started scoring a few hits on David Cameron by stepping outside the new Labour comfort zone - attacking health service privatisation and help-the-rich tax schemes. But Balls is stuck in 2010. Why get Labour or the unions to supply a research assistant when management consultants like PwC will help?
After all, PwC knows all about tax. It helped both Vodafone and Goldman Sachs on their controversial tax deals, spiriting billions away from the Treasury and onto corporate balance sheets.
Balls isn't alone. PwC also supplied other Labour shadow ministers with research assistants.
Since 2010 PwC has spent £270,000 giving Labour's ministers little helpers.
Shadow ministers getting free help from the firm include shadow business secretary Chuka Umunna, shadow communities secretary Caroline Flint, plus Jim Murphy for defence and David Hanson for Treasury issues.
When Ed Miliband reshuffled his shadow team the positions changed, but PwC stayed the same.
Umunna replaced John Denham, but the management consultants supplied assistants to both. The advice may be free, but it will cost the party dear.
PwC was one of the main promoters of PFI and was also intimately involved in the financial collapse as Northern Rock's auditors.
It saddled the party with crap, "business-friendly" policies that still damage Labour's credibility.
Its influence on Balls doesn't help Labour's attempts to shrug off some of the failures of the last government.
Balls may not know what he is doing, but PwC does. It plays both sides of Parliament.
Before the last election it ran Frances Maude's "implementation team" which prepared Cameron's shadow ministers for government. Whichever way you vote, PwC wins.