A study conducted by German financial magazine Capital has found that the quality of income tax offices fluctuates greatly in Germany. The study, which tested all 572 tax offices in the country, said that every seventh tax assessment statement was found to be wrong while some offices had an error margin of up to 50 percent. "The principle of coincidence decides the net income after deductions," Kai Stepp, editor in chief of the magazine, said on Wednesday. The study checked the quality and competence of tax officers, their speed in preparing tax assessment statements and their readiness to help citizens. Across the country, citizens at every second tax office had to wait for more than eight weeks for their tax assessment statements. Only 11.4 percent of the tax authorities sent the statements within four weeks, 40 percent needed between four to eight weeks. While tax offices in Hamburg and in North Rhine-Westphalia fared the best, the study found that the worst tax authorities were in eastern Germany in Thüringia and Brandenburg.