What A PlugShare Score Really Means (& How It Could Be Better)

There’s been a lot of controversy recently about Electrify America’s charging stations. Sadly, many of them have multiple stalls down, strange startup problems, dead screens, and other issues that make charging tough or impossible in some cases. Ideally, you’d just pull up and plug in and not worry about things, but sometimes you’ve to to do something annoying like plug the car in again, switch stalls, or call for help.

While these problems are very real and Electrify America needs to improve, there are people who exaggerate the issues for various reasons, and make it sound like it’s literally impossible to charge at Electrify America stations. For some people, they’re Tesla fans (or stockholders) and think trashing other companies will make Tesla look better (or bring the stock out of the dumps). For other people, general hatred of EVs drives them to make it look worse than it really is. Plus, some people are just drama queens, and drama can be profitable in today’s pay-per-click media environment.

As is often the case, the truth is somewhere in between. Ask most drivers of non-Tesla EVs, and they’ll tell you that they’ve been annoyed and inconvenienced, but most won’t tell you they’ve ever been stranded by a broken station.

Can This Be Expressed With A Number? If So, It Ain’t Easy.

If you think about it for a bit, trying to explain how good or bad a charging station is can be challenging. There are so many things that could go wrong that will annoy different people to different degrees. For example, I used to drive a Nissan LEAF that would overheat at DCFC/Level 3 stations. Buying a Bolt EUV, and being able to not only get to the next charging stop, but get a 55 kW charge pretty consistently, is a huge improvement over what I was used to, even if EA is a little buggy. But, if you’re a former Tesla owner, the Bolt would be a pretty sub-par experience, and Tesla’s supercharger stations aren’t buggy, so you’d think pretty poorly of EA as well.

Trying to describe an EV charging station’s “goodness” with just one number is even tougher, and it’s a problem people in many different fields have run into. Even describing your pain on a scale of one to ten can be difficult enough that many doctor’s offices have visual aids.

When it comes to EV charging, there are so many aspects of charging that could be measured and quantified. You could come up with a percentage of stations that are up right now. You could come up with the percentage of the time people get stranded, or come up with a percentage of the time that each station is up and running. Or, the percentage of time each individual stall is up. Or, you could have individual drivers rate the station on how good it is, and average them.

There are downsides and upsides to each of those approaches. If stations are up 99% of the time, that’s still 3.65 days per year down. If you happen to show up in the middle of those three bad days, it won’t help you that the station is down only 1% of the time. Or, if 87.5% of stations are up, and the broken machine is the only one available, that’s still a very problematic experience for you. And the average subjective ratings? Everyone has different ideas of what a 1 is and what a 10 is, so that’s still not useful.

How PlugShare Tries To Do This

One of the problems I’ve seen come up for PlugShare is that different people have different ideas of how the score should work. For some people, a 10 rating is only deserved if it’s a flawless experience and all stations are up. For other people, a 10 rating just means you won’t get stranded, even if you run into inconvenience or delay. Not knowing exactly what the score means or how to report problems, people have even accused PlugShare of censorship for editing reviews and combining reports to one negative review.

It seemed pretty obvious that my friend Branden and PlugShare didn’t agree on what the PlugShare score means and how things should be reported, so I reached out to PlugShare and asked them whether drivers should be reporting every individual stall that’s down, or just whether they were able to get a charge at all. This is what they told me:

“If a driver visits a charging location and is able to charge successfully the system is designed to have their check-in reflect that they charge successfully and to mention issues they encountered in their comments.”

They also gave me a link to a help page with more details on how PlugShare thinks scoring should be done, what a score means, etc. The big thing that page emphasizes is that reviews should be honest, and not exaggerated. “Couldn’t charge” shouldn’t be used for a delay or for one stall down, for example, and “Permanently closed” should be reserved for a site that’s closed for good and not for a site that’s temporarily down or has minor problems.

The obvious thing here is that PlugShare seems to want their score to reflect the likelihood that you’re get a charge at all, or if it’s been down recently (only the last few check-ins are part of the score). It’s not a score where 10 means a perfect station, but it’s also not a percentage of stations currently up, either.

How This Could Be Improved

Personally, I think trying to distill a station’s status down to one number is too simplistic to really tell the story of a station’s reliability and quality of service. I’d move to a system of one binary status and three numbers.

First, there should be an UP/DOWN status on a station. This could be as simple as red or green.

Second, there needs to be an uptime rating. How often has each station and each stall been down?

Third, there needs to be an overall percentage of currently operational stations, or a fraction, like 3/4 or 8/8.

Finally, there should be some room for a subjective rating that’s averaged.

For example:

• Status: UP
• Stations working: 7/8 (87.5%)
• Uptime rating for past month: 99.3%
• Customer Rating: 82.7% (see complaints)

This wouldn’t be as simple as a single number, but it would at least let people be on the same page when describing stations, and make sure every aspect of station reliability and pleasantness gets shared.

Update From PlugShare:

After reading the above article, PlugShare reached out to me. Here’s what they had to say:

“I just wanted to let you know that we have it on our roadmap to address many of the areas you called out. We’re just a very small team with a lot of projects we’re working on, but this is certainly a priority.”

So, it’s pretty clear that PlugShare does listen to us users, and they do plan to improve upon this aspect of the app and website. Be sure to keep sharing constructive criticism of the app for the team to consider!

 ‌

Featured image: a screenshot from PlugShare.com showing a repeated negative rating (something PlugShare doesn’t like).