basis (e.g. 16/31 of the monthly charge) or may be more complex if only week days are being charged or a standardized month is being used (e.g. 28 days, 30 days etc.) Accrued expense Accrued expense is a liability whose timing or amount is uncertain by virtue of the fact that an invoice has not yet been received. The uncertainty of the accrued expense is not significant enough to qualify it as a provision. An example of an accrued expense is a pending obligation to pay for goods or services received from a counterpart, while cash is to be paid out in a later accounting period when the amount is deducted from accrued expenses. Under International Financial Reporting Standards, this difference is best summarized by IAS 37 which states: To add to the confusion, some legalistic accounting systems take a simplistic view of accrued revenue and accrued expenses, defining each as revenue or expense that has not been formally invoiced. This is primarily due to tax considerations, since in some countries, the act of issuing an invoice creates taxable revenue, even if the customer does not ultimately pay and the related receivable becomes noncollectable. Accruals in payroll In payroll, a common benefit that an employer will provide for employees is a vacation or sick accrual. This means that as time passes, an employee accumulates additional sick leave or vacation time and this time is placed into a bank. Once the time is accumulated, the employer or the employer's payroll provider will track the amount of time used for sick or vacation. Length of service For most employers, a time-off policy is published and followed with regard to benefit accruals. These guidelines ensure that all employees are treated fairly with regard to the distribution and use of sick and vacation time. Within these guidelines, the rate at which the employee will accumulate the vacation or sick time is often determined by length of service (the amount of time the employee has worked for the employers). Trial period In many cases, these guidelines indicate there is a trial period (usually 30 to 90 days) where no time is awarded to the employee. This does not prevent an employee from calling in sick immediately after being hired, but it does mean that they will not get paid for this time off. However, it does prevent an employee, for example, scheduling a vacation for