Identifying Variables of Decreased Alertness in Railroad Workers
Identifying Variables of Decreased Alertness in Railroad Workers
Steven M. Smith, Jacqueline D. Kloss, PhD, Mary V. Spiers, PhD
Department of Psychology, Drexel University
Background
•
Railroad workers who report reduced alertness are more prone to human factors accidents.
•
Sleep length and quality are known to contribute to change in alertness. What is not known are specific factors associated with change in alertness throughout the workday.
Aims
1. Determine the degree to which schedule type
(a. split shift; two separate shifts on same day and b. continuous shift) and average hours worked per week contribute to change in alertness throughout the workday, beyond sleep length and quality.
2. Explore the association between an aggregate measure of stress and change in alertness.
Method
•
Participants were healthy adult males (n=506; ages
20 to 60+) who completed a demographic and general health questionnaire in addition to an activity journal for 14 consecutive days.
•
Change in alertness was derived from the difference in alertness ratings at the start and end of the workday (Likert scale 1 very sleepy – 5 very alert).
•
Overall stress was an aggregate measure of subcategories (e.g., stress due to lack of sleep, stress due to job security, etc.).
Results
Aim 1
Block Independent Variable
1 Starting Alertness & Age
2 Sleep Quality & Sleep Length
3 Schedule Type
4 Average Hours Worked Per Week
R 2
Change
F
Change
df
1
.06
.14
.04
.03
14.83
38.46
20.10
16.47
df
2 p
Change
2 436 p < .001
2 434 p < .001
1 433 p < .001
1 432 p < .001
Aim 2
Block
1
Independent Variable
Overall Stress
R 2
.05
F
26.40
df
1 df
2 p
value
1 482 p < .001
Conclusions
•
Replicated finding that sleep length and sleep quality account for the most variance in change in alertness. Above and beyond sleep factors, schedule type and hours worked per week account for 7% of the variance in change in alertness.
•
An overall aggregate stress measure accounts for 5% of the variance in change in alertness.
Future Directions
•
Explore the moderating effects of age, sex, race, and other demographic factors in relation to schedule type and hours worked in various blue-collar work populations.
•
Identify specific factors of overall stress that may account for change in alertness.
Acknowledgement: The authors would like to thank the Department of Transportation and Federal Railroad
Administration for publicly accessible data (Federal Railroad Administration, 2011).
