Certain practices common in the early United states make it easy for historians to underestimate the extent of American women's paid labor. Under the legal principle called coverture, married women had no legally recognized economic existence apart from their husbands and could not receive wages for their work. Records of payments for outwork (work performed in the home on a piece-rate basis) show male names as wage recipients. One has to look in the columns recording the amount of work completed to see that female names are listed as producers. Furthermore, most wage laborers were paid partly in goods and received cash wages only quarterly or once or twice a year. The infrequency of such payments has sometimes made it difficult for historians to recognize them as wages.