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Behind the scenes with MBTA data.

MBTA passengers can sign up to receive “T-Alerts” to get information about service delays. The alerts arrive via email or text, and subscribers specify which segments of service are of interest to them.  Because service disruptions can be complex and tend to unfold over time, there is a constant trade-off between the timeliness of sending the alert and the accuracy of the estimated length of impact to service. We discovered through customer feedback, including in our monthly satisfaction survey, that our passengers were relatively dissatisfied with our approach. In March 2018, two departments collaborated to design and implement a different alert system. Our job at the Office of Performance Management and Innovation (OPMI) was to evaluate these changes: did our passengers notice the changes, and if so, are we moving in the right direction of better communication at the critical points in our passengers’ experiences? 

Background

Every month, we send a survey to a few thousand passengers who have signed up to give us feedback on our system. Respondents report on their most recent trip and answer questions about various aspects of their experiences. We measure their satisfaction on a multitude of topics, and consistently using the same 7-point scale, with 1 as “Extremely dissatisfied, 4 as “Neutral,” and 7 as “Extremely satisfied.” This allows us to track big picture trends over time, and do deep dives into different topics while maintaining a level of comparability. From September 2017 through March 2018, three of our surveys included questions that specifically address T-Alert satisfaction. 

In September 2017, of our panel respondents who received T-Alerts, 43% thought that T-Alerts did not arrive in time for them to make decisions, and 37% did not think the alerts accurately reflected the service they were experiencing. When asked about their overall satisfaction with T-Alerts, respondents reported an average satisfaction of 4.74, which is between “neutral” and “somewhat satisfied” on our scale. In December, none of their answers to these questions had changed. To put this in perspective, respondents were slightly more satisfied with T-Alerts than with MBTA communication overall, and less satisfied with T-Alerts than most other channels of communication, including countdown signs in stations and the MBTA website.

Focus on Timeliness

Based on customer feedback through many channels, the Customer Technology Department collaborated with the Operations Control Center to redesign the alert system to fit an overarching philosophy that values timeliness and transparency. 

In early March 2018, the new T-Alert system was released with three substantive changes. When a disruption unfolds, and there is still uncertainty with how it will affect service, the new strategy issues alerts as soon as possible with the best information we have. As more information is gathered, relevant updates are sent out. The new strategy uses clear and straightforward language, and instead of classifying disruptions into the three ambiguous categories, “Minor/Moderate/Severe,” now the alerts provide estimates in minutes for how long the delay is expected to be. On the back end, there are new processes to ensure that alerts are cleared and closed out in a timely manner as well. 

These changes reflect an emphasis on being proactive and being willing to convey uncertainty. They prioritize speed over knowing the final outcome of the delay, and have a high emphasis on transparency. 

Measuring Satisfaction

In mid-March, we asked our passengers to rate their satisfaction with T-Alerts once again. 

We kept the wording of the survey question the same in order to keep their response unbiased; part of what we were looking for was if our passengers even noticed the change.  But first, we had to isolate the effect of the change from all the other factors that could have influenced satisfaction with T-Alerts (for example, weather patterns generally have an effect on satisfaction, and this effect is likely to show up between December and March). 

So, to mitigate possible confounding variables, we analyzed T-Alert satisfaction relative to other metrics collected in the same month. We chose to compare satisfaction with T-Alerts to satisfaction with communication overall, as we believe any changes in overall happiness would similarly affect satisfaction with individual channels as well as patterns overall. This relative satisfaction between T-Alerts and communication satisfaction isolates our independent variable of interest.

Chart showing the change in satisfaction from the December to the March survey.

The chart above shows the difference between panel respondents’ satisfaction with various channels of communication and their satisfaction with MBTA communication overall. Positive values signify that people are more satisfied with that specific channel, and the larger the value, the larger the gap in satisfaction. In December people who used third-party apps reported the highest level of relative satisfaction (0.38 pts more satisfied than with communication overall). T-Alerts hovered around 0.1 points more satisfied. 

The difference between the March “gaps” and the December “gaps” measures the relative change in satisfaction between December and March. Larger differences in gaps signifies larger gains of improvement. T-Alerts showed the greatest improvement relative to communication satisfaction; passengers reported a 0.2 points increase in relative satisfaction, which is a value we consider both significant and meaningful.  This increase in satisfaction disrupted the order of satisfaction of the channels; in December, passengers who used Third party apps were most satisfied with their respective channel, but in March, people who used text message T-Alerts reported the highest levels of satisfaction.   

There are similar improvements in satisfaction with Twitter. We expected Twitter satisfaction to increase because the changes in alert strategy detailed above were also changed on the MBTA Twitter feed. 

Given the unique increase in T-Alert satisfaction ratings, we believe passengers are more satisfied with T-alerts due to our intervention. 

Takeaways

There are two main takeaways for us from this experiment.

First, we successfully implemented a change that made our passengers measurably more satisfied with our communication. Currently over 70,000 of our passengers are subscribed to T-Alerts. We strive to match our communication to their preferences, especially in moments of service disruption. Prior analyses have repeatedly shown that quality communication is extremely valuable to our passengers and that it plays a significant role in their overall satisfaction with our system. These changes demonstrate that we can have a positive impact on our passengers’ experiences in the short term, while we conduct ongoing work system-wide. 

The second takeaway is that we are able to use data to make hypotheses about how to improve communication, implement a change, and then test whether it has the desired impact. We will continue using analysis from customer surveys to inform how we can improve and confirm if it worked. If you would like to help us, please sign-up for our monthly customer opinion panel.