Continued claims, also referred to as insured unemployment, is the number of people who have already filed an initial claim and who have experienced a week of unemployment and then filed a continued claim to claim benefits for that week of unemployment. Continued claims data are based on the week of unemployment, not the week when the initial claim was filed.
Source: Business Cycle Developments, March 1964, For 1949-1962 Data; August, 1966 And Following Months For 1963 And Later Data. This NBER data series m08310 appears on the NBER website in Chapter 8 at http://www.nber.org/databases/macrohistory/contents/chapter08.html. NBER Indicator: m08310