. 2017 Aug 15;34(16):2396–2409. doi: 10.1089/neu.2016.4819

Appendix D:

The Influence of Attrition on the Estimation of Predictors
D1. Descriptions of Three Scenarios of Attrition

Scenario	N	Mean score on Rivermead Post Concussion Questionnaire (SD)
Patients lost to follow-up not included in the analyses (analyses in this paper)	277	8.8 (10.0)
Scenario 1: Patients lost to follow-up have a relatively favorable outcome^‡	476	6.6 (8.8)
Scenario 2: Patients lost to follow-up have an average outcome	476	7.7 (9.0)
Scenario 3: Patients lost to follow-up have a relatively unfavorable outcome	476	11.8 (10.4)

^{^‡}

199 patients lost to follow-up received a random score on the Rivermead Post Concussion Symptoms Questionnaire with a mean of 0.0 (25^th percentile patients included at 6-month follow-up) and a standard deviation of 10.0 (standard deviation patients included at 6-month follow-up).

199 patients lost to follow-up received a random score on the Rivermead Post Concussion Symptoms Questionnaire with a mean of 5.0 (Median (50^th percentile) at 6-month follow-up) and a standard deviation of 10.0 (standard deviation patients included at 6-month follow-up).

199 patients lost to follow-up received a random score on the Rivermead Post Concussion Symptoms Questionnaire with a mean of 15 (75^th percentile patients included at 6-month follow-up) and a standard deviation of 10.0 (standard deviation patients included at 6-month follow-up).