1. The Explicit Indication of Design Objectives
a. Were the objectives stated?
The study into ergonomic extended screw guns focused on improving the working conditions for carpenters, as an attempt to reduce the number of back injuries, strains and sprains endured by the carpentry community. The introduction to the study discusses how, in 2005, carpentry was the second worst construction-based industry for its workers contracting carpal tunnel syndrome, tendonitis, sprains and strains, and back injuries.
b. Were they clear and appropriate?
Their aim was very clear: to produce a product which enabled carpenters to do their work without constantly being bent over or knelt down, leading to a long-term injury.
c. Were they measurable?
Having started the study with quantifiable data, their aims would be easy to quantify by monitoring the future health of the subjects. They also looked at the qualitative data by talking to the carpenters and getting direct feedback throughout the study.
2. Method of Market Research
a. How was it done?
The study was carried out by asking each carpenter to use the exact same tools: the un-ergonomic Milwaukee heavy-duty screwdriver (TSG), and the ergonomic extension screw gun: the Senco Durapsin (ESG). By using the same two screw guns across the study, they are standardizing their results. They also chose to compare the effectiveness of the manualfeed setting on the TSG and the autofeed setting on the ESG, because of the comparisons made on various websites that said that the ESGs were nearly all automatic and therefore enhancing their ergonomic ability.
The main focuses of the study were to examine the various effects that either gun had on the carpenters’ bodies and wrist movement, impact on the arm, position of the back were all measured. As part of the study, they should have also assessed the posture of each man: a lot of people naturally don’t stand up straight and this could ultimately affect their results and the carpenter’s health.
b. Was it appropriate?
Yes, the study assessed the various factors that could be contributing to the high number of back injuries suffered by Carpenters. The methodology used took into account the various factors including the men’s pre-existing posture, their tools and the comparison of the auto-feed compared to the manual.
c. What else could have been done?
In doing this, they are adding another dimension to their study: does the autofeed also help to increase the ease of use for the carpenters? In order to gain further information, ten of the commercial construction carpenters were asked to stay for thirty minutes after work one night to discuss their use of ESG tools on that site and were paid for their time. By paying the men, they are more likely to get in-depth responses.
During the study, they measured the pre-existing back problems using a lumbar motion monitor; they ensured that the number of screws used per tool was equal; they measured the force of the movement of the gun and estimated its effect on each man; and a goniometer was used to assess the movement of their wrist.
3. Use of Subjects and Scenarios
a. Descriptions of the subjects and scenarios
The study was carried out on fifteen skilled carpenters from varying construction backgrounds (commercial construction, residential sites and apprentices). Using a range of carpenters with a broad range of experience will give the testers the ability to examine the effect of a more ergonomic tool on a range of people with varying degrees of pre-existing wrist weakness.
b. Discussion of the appropriateness of the subjects and scenarios
When assessing the quality of their wrists prior to the study, only twelve men’s data was used due to there being a problem with the sensor. This immediately means that a fifth of their results will be out of context and therefore, should not bear any relevance on the outcome of the study.
4. Use of measurement tools
a. Description of the measures used
The tools used to measure the various attributes of the men’s bodies and their use of the two screw guns was vital to the complete measurement of the study. With the focus being placed on the effect of these tools on the men’s bodies, they had to measure every last effect.
b. Discussion of the appropriateness of the measure for that product
Also, the range of carpenters that were used meant that they had to carry our in-depth measurements on an individual basis as the men would vary in age and length of time working on construction sites, meaning that there would be a flux in the results if this wasn’t considered fully.
c. The cost vs. usefulness of the measure
The study found that whilst the screws used in an ESG were slightly more expensive, they increased productivity as carpenters took, on average, 9 seconds to place and insert a screw using the ESG, compared to 24 seconds per screw with a TSG.
d. Your comments about whether this measure will be of use in your future work as an industrial designer
In future work, assessing this will be imperative to ensuring my own results and placing emphasis on efficiency rather than cost is important for gaining fully explained results.
5. Conclusions of the Study
The results of this study showed that by using an ESG instead of a TSG it reduces the risk of back injury because the ESG decreases the need for awkward movement and position during use. The wrist is also in a better place for use and consequently the risk of injury is also decreased there.
a. Were they appropriate?
On a practical level, the carpenters would need more training to teach them how to use and repair the ESG correctly to further eliminate potential for injury and time wasting. The study also recommends improvements to ESG such as angling the handle slightly to further limit awkward handling of the tool. They also discussed how there is a substantial problem with the amount of looking down and the potential neck injury that could pursue, although they offered no immediate resolution to this.
b. Critical analysis of the findings.
These conclusions are useful as they demonstrate the original hypothesis and have examined the ergonomics of the two screw guns in depth and can help to reduce injury in the future whilst making further recommendations and predictions of the problems that could arise from the ESG.
c. Were they useful to you as an industrial designer?
Although this was only a field study, it is helpful to my own future investigations as it as an exemplary demonstration of looking at all potential problems, measuring every last factor and concluding with useful information.
Albers, J. T. et al. “Ergonomic evaluation of an extension screw gun to improve work postures.” Occupational Ergonomics 8. (2008): 27-40. Electronic.