The relationship between firm size and quality of services performed

Audit quality and variables with important effects on it, is one of the interesting subjects that researchers concentrate on it. Important role of auditors in the society with important economic and social outcomes is maybe one of this attention reasons. Auditor size is one of the known effective variables on audit quality. Audit quality is measured by a variety of variables in the literature. Auditor size, earning management, going concern modifications and type of the audit report are some of used variables. Dichotomizing the Big firms from non-Big firms is a method that is frequently used to define audit firm size. In this research that performed on 100 companies in the Tehran Stock Exchange market during the years between 1385 until 1387, we measure the audit quality by the number of modification paragraphs of the audit report. In the other hand four methods is introduced to measure the auditor size and each method is examined in a separate hypothesis. In three hypothesis auditor size is measured by auditor share of the Tehran Stock Exchange market based on total assets, revenue and the number of the clients. In the last method in accordance with previous Iranian researches, Audit Organization assumed as large and other auditors, as small auditors. Results accept first three hypothesizes and reject the last one. In other words when auditor size measured by auditor share of market, it is found effective on audit quality. Results also indicate that audit quality of audit organization does not have a considerable difference relative to other auditors.