Multiple modes of data collection are progressively being used more often to reduce the cost of rigorous samples, maximize response rates/coverage, or to make data collection more cost efficient for longitudinal surveys. Depending on the survey content, such a change has the potential to generate mode effects. While the body of literature is growing, much remains to be learned about the conditions under which researchers should expect to observe a mode effect and what avenues of recourse are advisable when a mode effect is observed. In this presentation we present the results of a randomized mode experiment embedded in the second wave of The Portraits of American Life Study (PALS). The baseline survey was administered in 2006 with computer-assisted personal interviewing (CAPI) and audio computer-assisted self-interviewing (ACASI) for a module of sensitive items. The second wave, conducted in 2011, features a sequential, mixed mode approach beginning with Web and followed-up with CATI. A random subset of the Wave 2 respondents was assigned to a “CATI only” condition with no Web option. We present our methodology for exploring mode differences and correction of mode effects.