The analysis of the study conducted by McEvoy et al. reveals that though he study has certain limitations, the authors used proper sampling methods and analysis techniques and made appropriate conclusions.
The purpose of the study was to explore the effects of drivers’ use of mobile phones on the risk of a crash. Both research question and exposure with the main outcome were clearly defined by the authors. The research questions included whether the use of mobile phone before the crash is associated with an increased likelihood of crashing and whether the risk differs for hands-free and handheld phones. The main exposure was the use of mobile phone while driving a car and the main outcome of interest was the car crash.
The study population included drivers aged above 17 years who were involved in a crash during the period between April 2002 and July 2004, visited emergency departments, and reported owning or using a mobile phone (McEvoy et al. 428). Such population was chosen to address the research question due to the presence of both the exposure and the main outcome of interest in most of the cases. The study population, the process of selecting the study subjects, and exclusion criteria were clearly defined by the authors. The study population can be considered unbiased though its size was rather small.
The authors used a case-crossover design to answer the research questions. Such design is appropriate for the discussed study, as the exposure is brief and the rise in the risk of the main outcome is transient. The data needed for conducting the research were collected in emergency departments from the drivers injured in a car crash. The data were collected through interviews including the questions related to demographics, patterns of driving and phone use, details of a crash, and the type of the phone. Since interviews cannot be regarded as a reliable source of information, the authors obtained the necessary data from the medical records and records of participants’ mobile phone use. Such data collection scheme appears to be adequate as it enabled the researchers to compare the self-report data with the data from the phone company and recheck the details in cases of contradictions. For the statistical analysis of the gained information, the authors conducted “matched analyses using conditional logistic regression to calculate the odds of having an injury crash in association with mobile phone use” (McEvoy et al. 429). The primary analysis included the 1: multiple matching related to the comparison between the use of a mobile phone during the hazardous and control periods. 1: multiple matching also was used for the analysis of the subgroups (based on age, sex, and phone type). Such methods of analysis of the data can be considered appropriate, as they enabled the researchers to compare the relation between the outcome of interest and the control periods and subgroups. Such method contributed to the comprehensiveness of the results and the conclusions based on them.
The results were clearly presented by the authors and were appropriate to the statement of the research question. The tables used by the authors are rather easy to interpret. The results of the cross-over analysis revealed that 90% of participants were carrying their mobile phones during the trip that ended up with a crash though only 7% reported they used the phone during that trip. Phone records revealed that 9% of the subjects used mobile phones during the hazard interval. The use of a mobile phone during the hazard interval was associated with a fourfold increase in the possibility of crashing. No influence of sex, age group, or type of mobile phone factors was found. Moreover, handheld and hands-free phone use while driving was associated with nearly the same increased risk of crashing. Therefore, the results reveal that against a common belief that hands-free devices decrease the chances of crashing the risk in the cases of using such devices is almost the same as in the case of holding a mobile phone in hand. It shows that the usage of any mobile device while driving a car increases the risk of the car crashing four times.
Certain limitations of the study can be identified. The first one is related to the limited number of participants. A bigger sample size is needed to consider the conclusions related to the safety of the use of hands-free devices reliable. Besides, the data collection conducted with the help of interviews appears to be not effective enough, as the subjects could have reported the usage of hands-free devices to decrease their guilty in the accident. Therefore, the conclusions whether hands-free devices provide more safety for the drivers cannot be considered hundred percent valuable. One more limitation of the study is related to the fact that it is rather difficult to define the precise time of the crash. This fact influences the relevancy of data about the call records and the process of determining whether phone calls happened prior or after the crash. Though the researchers contacted the participants whose phone records data contradicted the information provided during the interview, the possibility of non-reporting cannot be excluded. The mentioned limitations could have affected the results of the study and decrease their significance.
Though certain limitations of the study can be determined, it still can be regarded as a reliable one. The main strengths of the study include its appropriate design and statistical methods. The selection of the subjects of the study can be considered free of bias, as sampling was conducted based on applying the objective criteria for exclusion. Besides, though certain limitations related to the lack of objective sources of information about the use of hands-free devices during the crash trip exist, the study sheds the light on the possibility of regarding the current belief about the safety of using such devices while driving a car as the unreliable ones.
The study can be considered relevant to the community as it reveals some of the crucial details influencing public health. Since car crashes are one of the major causes of serious negative health outcomes for the population, the findings of the study are crucial to establishing the effective system of preventing the car accidents. The findings proving the increased likelihood of car crashes in the cases of the usage of mobile phone while driving need to be used for the creation of policies prohibiting the usage of a mobile device while being on the road. Such policies could improve public health and decrease the number of car accidents casualties.
Though the article provides rather persuasive information about the investigated issues, certain improvements to the study could have been made, including extending the sample size and using more unbiased sources of information about the usage of hands-free devices during the crash trips. The anonymous form of interviewing would have been more appropriate, as it would have excluded the possibility of non-reporting based on legal or social causes. Future studies investigating the issue are needed since most drivers continue using mobile phones while driving, as the studies conducted by McEvoy, Stevenson, and Woodward (633) and Gras et al. (352) revealed. The next step in the research progression should include the investigation of the effects of using a mobile phone for text messaging on the likelihood of car crashing, as Hosking, Young and Reagan found a high prevalence of text messaging while driving (590).
References
Gras, Eugenia, Monica Cunill, Mark Sullman, Montserrat Planes, Maria Aymerich, and Silvia Font-Mayolas. “Mobile Phone Use while Driving in a Sample of Spanish University Workers.” Accident Analysis and Prevention 39 (2007): 347-355. Print.
Hosking, Simon, Kristie Young, and Michael Reagan. “The Effects of Text Messaging on Young Drivers.” Human Factors 51.4 (2009): 582-592. Print.
McEvoy, Suzanne, Mark Stevenson, and Mark Woodward. “Phone Use and Crashes while Driving: A Representative Survey of Drivers in Two Australian States.” Medical Journal of Australia 185.11/12 (2006): 630-634. Print.
McEvoy, Suzanne, Mark Stevenson, Anne McCartt, Mark Woodward, Claire Haworth, Peter Palamara, and Rina Cercarelli. “Role of Mobile Phones in Motor Vehicle Crashes Resulting in Hospital Attendance: A Case-Crossover Study.” British Medical Journal 331.7514 (2005): 428-430. Print.