In June of $2007,$ Frozen Food Express Industries reported that its auditors found material weaknesses in its internal financial controls. The PCAOBs Auditing Standard No$.2$ requires that the auditor form an opinion on the effectiveness of controls. If any deficiencies exist, they should be reported in writing to management and the audit committee. The existence of a material weakness requires the issuance of an adverse opinion. What are three types of possible deficiencies?