This paper reports the performance of a representative sample of 747 students (52.5% female), from 2nd to 5th year of elementary education from private and public (83.8%) schools of Sao Paulo city. The children performed the Form A of Word Reading and Spelling Task (WRST) containing 48 low-frequency words presented in a card. Data were analyzed using models of Item Response Theory. We observed high levels of accuracy. The analysis selected 24 items, which presented low to moderate discrimination and difficulty indices. There were mean differences between grades, but not sex or school type. We report percentile norms for the grades for the WRST´S (Form) Reduced Version. The results support preceding studies with the word decoding tasks in Brazilian Portuguese, which attested to the quasi-regular character of that language.
