Algorithmic Bias in Google Searches for Political Parties and - PowerPoint PPT Presentation

Algorithmic Bias in Google Searches for Political Parties and Candidates Johannes Nakayama, Nils Plettenberg, Laura Burbach, André Calero Valdez Human-Computer Interaction Center, RWTH Aachen University

The Datenspende BTW17 Dataset

search terms search terms … database search terms Ø 1647 searches per day 4000 participants

parties: candidates: ‘CDU’ ‘Angela Merkel’ ‘CSU’ ‘Martin Schulz’ ‘SPD’ ‘Christian Lindner’ ‘FDP’ ‘Katrin Göring-Eckardt’ ‘Bündnis 90/Die Grünen’ ‘Cem Özdemir’ ‘Die Linke‘ ‘Sahra Wagenknecht’ ‘AfD’ ‘Dietmar Bartsch’ ‘Alice Weidel’ ‘Alexander Gauland’

Can we find evidence for personalization in the dataset?

First approach set intersection: first three/six/nine results

A C B D C A D G E F F B G H H E I I

A C B D C A D G E F F B G H H E I I

A C B D C A overlap of 66.67 % repeat for every list with every other list compute mean

downside: only rough order effects

Rank-biased overlap (RBO) (Webber et al. 2010) Result 1 Result 1 Result 2 Result 2 Result 3 Result 3 Result 4 Result 4 Result 5 Result 5 Result 6 Result 6 Result 7 Result 7 Result 8 Result 8

How does RBO work? Identical Lists Entirely different Same items, reverse items order User 1 User 2 User 1 User 2 User 1 User 2 A A A K A J B B B L B I C C C M C H D D D N D G E E E O E F F F F P F E G G G Q G D H H H R H C I I I S I B J J J T J A RBO score: 1.0 RBO score: 0 RBO score: 0.5116076

Last 5 items different How does RBO work? User 1 User 2 A A B B 1st item different 3rd item different C C User 1 User 2 User 1 User 2 D D A K A A E E B B B B F F C C C K G G D D D D H H E E E E I I F F F F J J G G G G K P H H H H L Q I I I I M R J J J J N S O T RBO score: 0.7297158 RBO score: 0.8747158 RBO score: 0.901564

Similarity of Search Results

T-test significant differences between RBO scores of parties and candidates t = 27.4, p < .001

H o w c a n w e e x p l a i n t h e d o w n w a r d t r e n d ?

Search Volume no absolute values only relative scores Trends

Summary significant difference between parties and candidates dependence between RBO scores and search volume

Future Work R T RBO package location content analysis (already in progress)

open data and all analyses available at: osf.io/e598k