Category Archives: featured

The Human Factors of Rock Climbing – A matter of life and death

A tragedy occurred last week in West Virginia where a rock climber died apparently due to a human factors issue with her gear. This text comes from a commenter on Rockclimbing.com:

The climber was Karen Feher from Midlothian Va. She climbed to the anchor of Rico Suave and clipped in direct. Her setup: She had two thin dyneema slings girth hitched to her harness. At the end of each sling was a locking carabiner held in place with a rubber Petzl keeper…She clipped a locker to each bolt and probably called off belay. I’m unclear if she was going to rappel or lower. It doesn’t matter. She fell to the ground.

The day after the accident a local climber named Craig (last name?) climbed to the anchor and found a locker on each bolt with a Petzl String still affixed to each one. Both Petzl strings were torn on the side.

Let me give a little background on the gear so you can understand what seems to have happened:

Climbers can affix themselves to the wall with equipment that has carabiners on both ends. This allows them to clip themselves to one side and clip the other to the wall. These can come in different varieties, and two types are illustrated below.

The first type consists of a sewn sling between the two carabiners. It is sewn tightly in multiple places to make sure that it holds tightly to the two carabiners.

A "quickdraw" with two carabiners
Notice the larger and smaller holes in each end. One holds a carabiner loosely to the rock while the other holds a carabiner more tightly on the rope end.

Notice on one side it is sewn so the carabiner hangs loosely and on the other side it is sewn tightly, so that it holds the carabiner almost immobile. The reason for this is to allow the side connected to the wall to swing freely as the rope moves, which keeps the rope movement from jarring or upsetting protection put into the rock. The other end that is connected to the rope keeps the carabiner from moving around and possibly turning sideways.

The second type (below) consists of a nylon sling doubled over between the carabiners. The benefit of this kind of sling is that it can be changed in length – by doubling and tripling it, it can either be 4′ long, 2′ long, or just a foot long. However, notice both sides are the same. The benefit of having one loose side and one tight side does not exist here. Incidentally, this is the type of sling I use almost exclusively.

A simple loop connects the two carabiners
A simple loop connects the two carabiners
The sling has now been doubled over to shorten it

There is one way to turn the second type of sling into an approximation of the first type: a rubber band. Not only can you do this with a plain rubber band, there are some specifically sold for this purpose.

The rubber band holds the rope end tight while allowing the other end to swing freely
Again, rope holds one end, this time with sling not doubled over

The problem with this solution lies in the changes to visibility and function that the rubber bands can have when the slings are doubled-over incorrectly.  Click here for a video explaining what can go wrong.

Essentially, the sling can become almost invisibly connected ONLY by the rubber band. I am sure no one would like to think of hanging 100 feet from the ground by a grocery store rubber band.

The additional component to the tragedy that prompted this post is that both of her slings were attached only by the rubber band. Climbers build redundancy into their systems to prevent accidents like this, but here both failed.

iPad is everything the Kindle isn’t (for my use cases)

I acquired an Apple iPad a few weeks ago and am very impressed with it. Just as background, i’m a PC person (a desktop at work, home, and a Fujitsu P1620 ultramobile tablet, all running Windows 7).  My portable computer weighs about 2.5 lbs but the iPad is a full pound lighter and the battery lasts about 10 hours. Less than the Kindle, but much more than my laptop.

Like my previous look at the Kindle, this isn’t a review, but just some thoughts after using the iPad for a few weeks as an academic. To cut to the chase, it’s everything the Kindle isn’t. If you remember from my post on the Kindle, I loved the e-paper screen but lamented the many limitations, the most severe of which was the inflexibility with note-taking and reading PDFs.

That observation was recently re-iterated in several test trials of the Kindle in academic settings (see my previous post, and the results of another academic trial of the Kindle at UVA).

That inflexibility I mentioned was certainly felt by the students in the UVA trial:

“You must be highly engaged in the classroom every day,’’ says Koenig, and the Kindle is “not flexible enough. … It could be clunky. You can’t move between pages, documents, charts and graphs simply or easily enough compared to the paper alternatives.’’

Koenig learned of the dissatisfaction from a mid-term survey that concluded with two key questions: Would you recommend the Kindle DX to an incoming Darden MBA student? A total of 75 to 80 percent answered “no,” says Koenig.

The iPad, while not perfect, fixes many of these problems.  Navigating the document is fast and fluid and you can view books and PDFs zoomed in, two-pages-at-a-time, or full page.  Note-taking is also very easy and consistent with my usual workflow (marking up documents).  So with that, here are some apps I use frequently for work:

iAnnotate

I am generally a pretty paper-less person who scans everything into a PDF.  One of my favorite PDF readers is iAnnotate which not only lets me view PDFs but annotate and then email them:

The application has a PC-based component that will serve your iPad PDFs stored on your computer so you have access to your complete library from your iPad. After you’ve marked up your PDF, you can upload the marked-up copy directly to your computer.

Evernote

The other app I use frequently is Evernote which is a note application that syncs to a web service.  The notes are then accessible from the web, your mobile phone, or your desktop computer.  Another thing I’ve realized is that the landscape software keyboard (shown below) is surprisingly touch-typeable.  I think I can achieve about 85% of my touch typing speed.

Evernote

Keynote

Finally, I also use the iWork apps (Pages, Keynote, and Numbers) but Keynote seems to be the most useful.  The others have very wonky conversion with Word and Excel files.  Keynote seems to handle Powerpoint files adequately:

Keynote

Facebook and Privacy: A Guest Post by Kelly Caine

Many of my friends have threatened to leave Facebook because of their concerns over privacy, but for the first time, this week one of them actually made good on the threat.

In his “Dear John” letter, my friend Yohann summarized the issue:

I don’t feel that I am in control of the information I share on Facebook, and of the information my friends share… FB has total control of (some of) my information, and I don’t like that.

It’s not that Yohann didn’t like Facebook–he did. He liked being able to see his friend’s latest photos and keep up with status updates. The problem was that Yohann (who is, by the way a very smart, tech savvy guy) felt unable to use the Facebook user interface to effectively maintain control of his information.

The root of this problem could be one of two things. It could be that Facebook has adopted the “evil interface” strategy (discussed by Rich previously on the human factors blog), where an interface is not designed to help a user accomplish their goals easily (a key tenet of human factors), but is instead designed to encourage (or trick) a user to behave the way the interface designer wants the user to behave (even if it’s not what the user really wants). Clearly, this strategy is problematic for a number of reasons, not the least of which from Facebook’s perspective is that users will stop using Facebook altogether if they feel tricked or not in control.

A more optimistic perspective is that the problem of privacy on Facebook is a human factors one: the privacy settings on Facebook need to be redesigned because they are currently not easy to use.  Here are a few human factors issues I’ve noticed.

Changes to Privacy Policy Violate Users’ Expectations

Facebook’s privacy policies have changed drastically over the years (The EFF provides a good description of the changes and Matt McKeon has made a very nice visualization of the changes).

Users, especially expert users, had likely already developed expectations about what profile information would be shared with whom. Each time Facebook changed the privacy policy (historically, always in the direction of sharing more), users had to exert effort to reformulate their understanding of what was shared by default, and work to understand how to keep certain information from being made more widely available.

Lack of Feedback

In general, there is very little feedback provided to users about the privacy level of different pieces of information on their Facebook profile. For example, by default, Facebook now considers your name, profile picture, gender, current city, networks, friend list, and Pages to all be public information. However, no feedback is given to users as they enter or change this information to indicate that this is considered public information.

It is unclear what is public and non-public information

While Facebook did introduce a preview function which shows a preview of what information a Facebook friend would see should they visit your profile (which is a great idea!), the preview function does not provide feedback to a user about what information they are sharing publicly or with apps. For example, you can’t type “Yelp” into the preview window to see what information Facebook would share with Yelp through Facebook connect.

You cannot preview what information Facebook shares with sites and apps

No Training (Instructions)

Finally, Facebook does not provide any training and only minimal instructions for users on how to manage privacy settings.

Solutions

Fortunately, there are some relatively simple human factors solutions that could help users manage their privacy without writing their own Dear John letter to Facebook.

In terms of user expectations, given the most recent changes to Facebook’s privacy policy, it’s hard to imagine how much more the Facebook privacy policy can change. So, from an expectations standpoint, I guess that could be considered good?

In terms of interface changes to increase feedback to users, Facebook could for example, notify users when they are entering information that Facebook considers public by placing an icon beside the text box. That way, users would be given immediate feedback about which information would be shared publicly.

Globe icon indicates shared information

Finally, in terms of training, it’s fortunate that a number of people outside of Facebook have already stepped up to provide users instructions on how to use Facebook’s privacy settings. For example, in a post that dominated the NYT “most emailed” for over a month Sarah Perez explained the 3 Facebook settings she though every user should know after Facebook made sweeping changes to their privacy policy that dramatically increased the amount of information from a profile that is shared publicly. Then, after the most recent changes (in April 2010) Gina Trapani at Fast Company provided easy to use instructions complete with screen shots.

Perhaps if Facebook decides to take a human factors approach to privacy in the future, Yohann will re-friend Facebook.

Kelly Caine PhD is a research fellow in the School of Informatics and Computing at Indiana University. Her primary research interests include privacy, health technology, human factors, hci, aging, and designing for special populations.

(post image from Flickr user hyku)