Perception of energy drink effects by student pilots

[HENDERSON Isaac L & Jose D PEREZGONZALEZ (2010). Perception of energy drink effects by student pilots5. Aeroscience (ISSN 2324-4399), 2013, pages 5-6.] [Printer friendly]

Perception of energy drink effects

Bliss & Depperschmidt carried out research into the perceived physical, psychological and practical effects of energy drinks among student pilots in 20101. This article provides a meta-analysis done on the original results.

Illustration 1 shows that, overall, the students agreed that energy drinks had some negative practical effects on flying but disagreed that they posed physical or psychological effects (when attending to the standard deviation for all three probes, the majority, 68%, of students held moderate opinions, and tended to either agree or disagree, rather than strongly agree or disagree, that energy drinks brought about negative effects).

Illustration 1: Probes by frequency of responses, mean, and standard deviation
Frequency of responses Statistics
Effects Strongly disagree (1) Disagree (2) Agree (3) Strongly agree (4) Mean StdDev
Psychological 12 47 28 3 2.24 0.72
Physical 5 41 40 4 2.48 0.67
Practical 2 11 42 5 2.83 0.62
(*Statistics based on the distribution of values (frequencies x anchor's value)

When attending to the effect sizes of the differences between probes (illustration 2), there was a small delta between perception of psychological and physical effects (d = 0.36), and a medium delta between physical and practical effects (d = 0.52). However, we can advance a similar argument than in Robinson et al (20124), that such effect sizes may not reflect a similarly important difference in scores between answers. The argument goes as follows: if we take each anchor as the centroid for a particular opinion (eg, '3, Agree'), it is reasonable to assume that such estimate actually ranges midway between the immediately lower and upper anchors (eg, any group score between 2.5 and 3.4 would be considered 'Agreement'). Thus, a difference of 0.5 points on this scale (ie, a difference that can differentiate between a centroid and the next range) may be a reasonably minimum degree of expected difference before considering such difference as something noteworthy7. Following this logic, then, most of the mean differences in agreement between probes were below such threshold and, thus, rather unimportant.

Illustration 2: Probes by effect size
Comparison Means difference Effect size (d) Interpretation
Psychological vs physical 0.24 0.36
Physical vs practical 0.35 0.52
Practical vs psychological 0.59 0.88 small
[Effect size (d) based on the average standard deviation (= 0.67)]

Study's scope

The sample used comprised only student pilots from a particular location in the USA. If at all, findings may only be generalized to similar populations. This being said, the study does give direction for future research on the effects of energy drink consumption because it identifies what areas student pilots believe are affected by such consumption.


Isaac L HENDERSON (2013). Massey University, New Zealand. (Isaac Levi HendersonIsaac Levi Henderson).
Jose D PEREZGONZALEZ (2013). Massey University, Turitea Campus, Private Bag 11-222, Palmerston North 4442, New Zealand. (JDPerezgonzalezJDPerezgonzalez).

Want to know more?

WikiofScience - Student pilots' perception of the effects of consuming energy drinks
A meta-analysis of Bliss & Depperschmidt's (2010) article done by Henderson & Perezgonzalez (2010).

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