 Claghorn was a frequent writer for magazines, and published her first book, "College Training for Women", in 1896.In a report for the New York Tenement House Department in 1901, Claghorn decried newspaper propaganda linking immigration to poverty,
and noted the particular enthusiasm for schooling displayed by Jewish immigrant children.In a study that she wrote in 1904 for the department, Claghorn foresaw that new groups of immigrants from southern and eastern Europe were not more likely to become impoverished, in the long term, than the previous immigrants from Britain and Germany.