 Gutman systematically took Fogel and Engerman to task on a variety of fronts.He noted the authors were extremely careless in their math, and often used the wrong measurement to estimate the harshness of slavery.For example, Fogel and Engerman assumed that slave couples moved west together with their owners, based on their analysis of probate records and invoices from slave sales in New Orleans, and therefore argued that the slave trade related did not destroy black families.