Investigating Wave 1 Effects on Poverty Calculations in the 2008 SIPP Panel

• Activity Number: 82
• Type: Contributed
• Date/Time: Sunday, August 3, 2014 : 4:00 PM to 5:50 PM
• Sponsor: Social Statistics Section
• Author(s): Ashley Edwards*+
• Companies: U.S. Census Bureau
• Keywords: 2008 SIPP Panel ; Poverty ; Wave 1 Effect

Abstract

Discontinuity in estimates of monthly poverty rates across successive panels of the Survey of Income and Program Participation (SIPP) has been a consistent feature of SIPP panels since the 1996 redesign. As investigated by Czajka, Mabli, and Cody in 2008, each SIPP panel since 1996 has reported Wave 1 poverty rates that were at least two percentage points higher than the final wave of the preceding panel. Additionally, within SIPP panels, monthly poverty rates experience a sharp decline over the course of Waves 1 to 2. This across and within panel phenomenon is often referred to as the "Wave 1 effect."

This analysis builds off the research of Czajka, Mabli, and Cody (2008) by investigating the Wave 1 effect present in the 2008 SIPP Panel, which covers the period from May 2008 to November 2013. Comparisons are made to the preceding 2004 SIPP Panel, covering the period of October 2003 to December 2007. Discrepancies in monthly poverty rates across panels and waves are investigated with a focus on sample composition changes and within-person poverty transitions across successive waves of the 2008 Panel.