The data in NC Tower is derived from the NC Common Follow-up System (CFS), a longitudinal repository of training, education, and workforce data maintained by the Labor and Economic Analysis Division of the North Carolina Department of Commerce. CFS data on public university students is submitted from the University of North Carolina General Administration, while CFS data on community college students comes from the North Carolina Community College System. Employment and wage information on individuals working in jobs covered by North Carolina's unemployment insurance laws is submitted to the CFS by the Division of Employment Security of the North Carolina Department of Commerce.
There are two reasons for the slight discrepancies between figures in NC Tower and counts of students and graduates published by the UNC General Administration and the NC Community College System. First, NC Tower focuses on counting unique individuals who were enrolled or graduating during a given school or program year (July 1 - June 30). Educational agencies often count degrees conferred, or count fall semester enrollment as part of their reporting requirements. These cause figures to fluctuate slightly from what is in NC Tower. Secondly, in order to maintain the integrity of CFS data, records with invalid Social Security Numbers are not loaded into the system. This prevents employment rates in NC Tower from being distorted by invalid SSNs that do not have a match in the wage data. However, it also means that student and graduate counts will be slightly lower than agency statistics. SSN verification removes approximately 1% of UNC General Administration records and 9% of NC Community College System records.
NC Tower looks at outcomes for individuals over 10 years (defined as 4-quarter periods) starting one quarter after their degree is conferred. For instance, if a student graduated in May of 2006 (i.e., Q2 2006), that student's employment status "After 1 Year" will be determined by the presence or absence of associated quarterly wage records in the next four quarters (i.e., Q3 2006, Q4 2006, Q1 2007, Q2 2007). Mean and percentile wages are based on the sum of the individual's wages over the four quarters in the year in question. Wage data is not adjusted for inflation, but simply reflects the actual dollar amounts of wages earned.
NC Tower always counts the number of unique individuals in the population in question. For example, if a student majors in both History and Sociology, that student will be counted once for the number of History students, once for the number of Sociology students, and once and only once for the total number of bachelor's degree students. This also applies for employment at the level of industrial sectors. If a graduate works several months at a retail clothing store before beginning employment in a local school during the first year after their graduation, that student will be counted once for employment in Retail Trade, once for employment in Educational Services, and once and only once for total employment.
NC Tower includes data on former students who are working in "covered employment" in North Carolina. "Covered employment" includes all individuals working for employers subject to North Carolina's unemployment insurance tax laws, as specified in Chapter 96, Article 2 of the North Carolina General Statutes. It is estimated that covered employment represents over 90% of North Carolina's total employment. However, employment that is not covered by North Carolina's unemployment insurance laws includes (but is not limited to):
Industrial sectors are based on NAICS "supersectors" used by the Quarterly Census of Employment and Wages program of the Federal Bureau of Labor Statistics. Within NC Tower, the Retail Trade sector, Educational Services sector, and Health Care and Social Assistance sector have been broken out of their BLS-designated supersector. Numbers of students working for employers with an unknown industrial sector are not reported.