Richard Jones, managing director of Alpha Risk Management, said the role of the security industry had widened considerably in the past few years.

Alpha Risk Management, whose clients include HSBC, MTV, S4C, Asda, Oasis, CNN, Fox News, the United States Department of Defense, NHS Trusts and motor sport organisations such as Rally GB and Silverstone, has also found itself becoming more involved in providing security for television companies, as well as events like outdoor music concerts.

Using the positive approach, alpha risk (Type I error) is concluding that the account is in error ([absolute value of E]>0) when it is not in error ([absolute value of E]=0) as shown in table 1 panel A.

Actual State: Actual State: [absolute [absolute Conclusion value of E]=0 value of E]>0 [absolute value of E]=0 Correct Decision Beta Risk (Type II Error) [absolute value of E]>0 Alpha Risk Correct Decision (Type I Error) Panel B: Negative Approach [H.sub.0]: [absolute value of E] [greater than or equal to] M (control point) [H.sub.a]: [absolute value of E] < M Decision rule: conclude [H.sub.0] if [absolute value of E] [greater than or equal to] M - Z[(1 - [alpha]).sup.*] [sigma] and conclude [H.sub.a] if [absolute value of E] < M - Z[(1 - [alpha]).sup.*] [sigma] , where [sigma] is the standard error of prediction for the past 24 months.

The alpha risk at [absolute value of E]=0 is the likelihood that an auditor will conclude that an account is in error when it is not.