Two Crossed Random Factors David A. Kenny

* Background Multilevel Modeling Nested *

* Data Structure There are two level 2 variables that have a crossed, not a nested, structure. Examples Participants and stimuli Participants and situations Participants and items *

* Illustration Study 1 from Smith–McLallen, A., Johnson, B. T., Dovidio, J. F., & Pearson, A. R. (2006). Implicit color and race preferences black and white: The role of color bias in implicit race bias. Social Cognition, 24, 46-73. *

Download Data Syntax Output

Details 67 participants non-white participants excluded * Details 67 participants non-white participants excluded one participant with more than 20% errors excluded 12 faces, 6 white and 6 black Implicit Attitude Test (IAT) Study *

Variables Face Participant (part) Race nested within Face * Variables Face Participant (part) Race nested within Face +1 White Face -1 Black Face Positivity Reaction times in milliseconds to each face when paired with a negative word minus when paired with a positive word. Larger numbers, more positive toward the face. *

Syntax MIXED positivity WITH race /FIXED = race * Syntax MIXED positivity WITH race /FIXED = race /PRINT = SOLUTION TESTCOV /RANDOM INTERCEPT | SUBJECT(face) /RANDOM INTERCEPT race | SUBJECT(part) COVTYPE(UN). Note that residual is the part x face interaction. *

White Faces Black Faces

Only variance that is statistically significant (p = Only variance that is statistically significant (p = .0185) is race of face effect for participants. Some participants show more bias than do others. About 89% of the variance is due to error, 1% due to participant differences, and 9% due to race bias differences due to participant. The race effect is 128.41 ± 78.47. Given a normal distribution of the race effect for participants, approximately 95% of whites show a bias in favor of whites.

Thank You! Aaron Smith-McLallen * Thank You! Aaron Smith-McLallen *

* Other Webinars References (pdf) Advanced Topics *