Some Thoughts on Accessible Real Time Informations

There are some cases in which a lot of information has to be output in real time. This creates some problems with digital accessibility. Here I would like to show a few ideas on how to solve the problems.

Note: WCAG SC 2.2.2 Pause, Stop, Hide does not apply to such applications. Although a permanent change takes place, which can be disturbing for people with cognitive disabilities, it is clearly a basic function of real-time trading, so it would not be mandatory to implement a pause mechanism here. As described below, a freeze function can be offered, but the trading provider can then no longer be held liable for trading based on incorrect information.

Problem description

The stock prices are updated at short intervals. A trader must be able to follow the changes in real time.

Both speech output and Braille display can only output information linearly, i.e. one after the other. If there are a large number of stocks and updates, these must be read out in the order in which the changes take place. This causes several problems:

Firstly, one is quickly cognitively overwhelmed when many values and changes are read out.
Secondly, if the value of four stocks is read out one after the other, the first value of the first stock may have changed when the value of the fourth stock is read out. This limits trading.

The problem cannot be solved with current or foreseeable technical means. There is no way to output information to blind people in a non-linear way. The options described here are therefore not perfect solutions.

Possible solutions

Option 1: Freezing a status quo

The trader has the option of freezing the status at a certain point. No updates will be sent.

Advantage: The blind trader can read all the values without being disturbed.
Disadvantage: A unique feature of trading is that the prices are always up to date. Furthermore, the blind person does not notice the new changes. He would therefore not be able to trade with valid values.

Option 2: Freeze the announcements

The trader can turn the announcement of updates on and off via the website. They still take place and if he focuses on a price, he gets its real-time value, but he does not get the other values read out automatically until he turns the function back on.

Advantage: If the trader focuses a value, it is always up to date.

Disadvantage: A blind person can only follow a limited number of values in a long table. He therefore always gets relatively little information. If he turns the announcement back on, he gets too much information at once.

Option 3: The changes are not announced at all

This is similar to option 2, except that there is no way to have changes announced automatically. The trader then only gets the current value if he has focused on a specific stock.

Advantage: There is no information overload for the blind person.
Disadvantage: As described above, it is then not possible for the blind person to follow many changes at once.

Recommendation

We recommend option 2. As described above, the problem cannot generally be solved with any conceivable means. However, a private trader is likely to have a rather limited portfolio. A blind person should be able to observe 10 to 15 stocks quite well. Due to the problem described above, it is unlikely that a blind person would trade professionally and observe dozens of stocks in parallel, and in any case it cannot be implemented comfortably with today's technology.

In my opinion, option 2 meets the basic requirements of accessibility as they can be implemented with the means available today. The blind person can also be made aware of this problem via a text on the trading page that is only visible to them. This eliminates any liability risks.

It would be important in any case that a blind trader can easily put together his own portfolio, i.e. the stocks that he wants to monitor. With a limited number of stocks, real-time monitoring is possible via the automatic output of changes.

It is also important that the values are not processed completely serially when values are output automatically. For example: four stock values are output serially, then it could be that the fourth value is output incorrectly because it has changed while the values are being processed by the voice output. The value output by the speech output/Braille display should, if possible, always correspond to the current value at that time.

Technically speaking, the area with the stock values can be set as an ARIA live region. The Offf attribute is set when the user freezes the announcement, otherwise the Polite attribute is set. The Assertive attribute should only be set for urgent information, as it always interrupts what the screen reader is currently outputting. If there are constant changes, the user would no longer be able to interact with the website because only the changes would be output. With polite, the change is output as soon as the screen reader is not outputting anything else. It is also important that only changes are output and not the entire live region when a value has changed.

Trading for the visually impaired

Another group for whom trading can be difficult are the visually impaired. They are simply unable to keep an eye on a large table and see whether and which values have changed. In our view, the best option here would be to change the table dynamically: For example, values that have just changed could be automatically pushed up.