Pilot Raw Data: Basic Analysis

This report uses main_2026-03-20.csv, pre_experimental_2026-03-20.csv, and PageTimes-2026-03-20.csv from /raw_data.

The analysis follows the hypotheses summarized in /text/presentation_BEEN.tex:

All main analyses below use the 53 participants who completed all 10 main rounds. The pre-experimental file contains 200 recruited participants in total, so the completion share is 26.5%.

The raw export does not contain a usable direct left-right self-placement item in this pilot. The ideology sections therefore use a derived issue-based right-leaning score built from three political statements in the pre-treatment survey:

Higher values indicate a more right-leaning issue profile.

Sample Overview

Metric Value
Participants in pre-experimental file 200
Participants who completed all 10 main rounds 53
Share of recruited participants who completed all 10 main rounds 26.5%
Mean movies rated per completer 4.09
Median movies rated per completer 4.00
Mean rating probability across all decisions 0.41
Mean decision time (seconds) 16.19
Median decision time (seconds) 12.00

How Many Movies Do People Rate?

Overall Distribution

Movies rated Participants Share
0 6 11.3%
1 2 3.8%
2 6 11.3%
3 8 15.1%
4 9 17.0%
5 7 13.2%
6 9 17.0%
8 3 5.7%
10 3 5.7%

Variation Across the Four Treatment Cells

Treatment Match type Domain N Mean movies rated SD Mean rate share
heterogeneous_neutral heterogeneous neutral 15 4.80 3.45 0.480
homogeneous_neutral homogeneous neutral 12 3.50 2.81 0.350
heterogeneous_political heterogeneous political 13 3.54 1.61 0.354
homogeneous_political homogeneous political 13 4.38 1.89 0.438

Variation Across the Two Treatment Factors

Factor Level N Mean movies rated SD Mean rate share
match_type heterogeneous 28 4.21 2.78 0.421
match_type homogeneous 25 3.96 2.37 0.396
domain neutral 27 4.22 3.19 0.422
domain political 26 3.96 1.78 0.396

Political Versus Non-Political Movie Content

This section speaks most directly to H3.

Movie content Movie side Decisions Rate probability Mean rating if rated Mean decision time (sec)
non-political non_political 265 0.415 3.59 17.06
political left 106 0.340 3.58 14.85
political neutral 53 0.547 4.03 16.19
political right 106 0.396 3.10 15.37

Do Left-Wing Participants Rate Left-Wing Movies More Often or More Positively?

This is descriptive only. The ideology grouping is derived from issue positions, not from a direct self-placement item, because that field is blank in this pilot export. The right-leaning group is small, so these comparisons should be read cautiously.

Ideology group Participants
left 46
right 7
Participant ideology Movie side Decisions Rate probability Mean rating if rated Mean decision time (sec)
left left 92 0.370 3.56 15.24
left right 92 0.435 3.08 15.32
right left 14 0.143 4.00 12.29
right right 14 0.143 3.50 15.71

How Does Rating Probability Change from Movie 1 to Movie 10?

Round Decisions Rate probability Mean decision time (sec) Median decision time (sec)
1 53 0.245 36.36 29
2 53 0.415 16.83 15
3 53 0.434 14.62 12
4 53 0.358 16.47 12
5 53 0.472 15.40 12
6 53 0.434 13.34 12
7 53 0.528 13.70 12
8 53 0.491 11.98 10
9 53 0.415 12.13 10
10 53 0.302 11.09 9

Does the Over-Time Pattern Vary Across Treatments?

This section is the most relevant descriptive check for H1 and H2.

Round heterogeneous_neutral heterogeneous_political homogeneous_neutral homogeneous_political
1 0.333 0.308 0.000 0.308
2 0.467 0.462 0.417 0.308
3 0.533 0.462 0.333 0.385
4 0.467 0.385 0.167 0.385
5 0.467 0.308 0.417 0.692
6 0.400 0.385 0.417 0.538
7 0.733 0.231 0.667 0.462
8 0.533 0.462 0.417 0.538
9 0.600 0.385 0.250 0.385
10 0.267 0.154 0.417 0.385

How Much Time per Decision Do People Spend from Movie 1 to Movie 10?

The first round includes the transition from the pre-experimental stage into the main task, so it is usually longer than later rounds.

Do Left-Wing or Right-Wing Participants Spend More Time on Left- or Right-Wing Movies?

The table and figure below use only left-coded and right-coded movies. The timing is the time spent on the decision page, regardless of whether the participant eventually chose rate or skip.

Participant ideology Movie side Decisions Mean decision time (sec) Median decision time (sec)
left left 92 15.24 12.5
left right 92 15.32 11.0
right left 14 12.29 9.0
right right 14 15.71 12.0

Exported Files

This report also writes reusable CSVs to the project root:

  • pilot_raw_participant_level.csv
  • pilot_raw_decision_level.csv
  • pilot_raw_treatment_summary.csv
  • pilot_raw_round_summary.csv