Welcome! Pick your number of letters and time delay between them. Click the "Run Test" button. Get your fingers on the keyboard. Be ready to type fast when the three second countdown timer runs out. For more information, please email me at firstname.lastname@example.org.
These are the names of the letters in the NPA. They are shown in groups of five as this is a good group size for memorization. The spellings of Alfa with an "f" and Juliett with an extra "t" are used as they are more internationalized.
Start with 1.0 points per letter. You start with as many points as you have letters. Choosing 10 letters would get you 10 points.
Lose 0.5 points for extra letters. Extra letters cost you 0.5 points. That extra letter can be anywhere in the answer. Choosing 10 letters and having all the right letters with one extra one would get you 9.5 points.
Lose 1.0 points for wrong letters. Providing a letter but having it be the wrong one cost you 1 point Choosing 10 letters and providing 9 right ones would get you 9 points.
Lose 1.5 points for missing letters. Not providing a a letter costs you 1 point. Avoid the urge to just tack a bunch of letters on at the end to make up the count. Doing so will likely cost you for both being wrong where the letters are supposed to be, and for having extra letters at the end. Choosing 10 letters and completely missing the first 2 will cost you 3 points. Putting "XX" at the end just to make up for it will cost you 1 more point for having two extra letters.
Convert to a percentage. Divide the number of points by the chosen number of letters. Then multiply by 100 to get a percentage. This is your accuracy for this question. The accuracy is provided so you can know your performance. But the calculation continues using your score, since your score naturally takes into account your accuracy.
Multiply by the number of letters.. Multiply your score by the number of letters. This gives you credit for taking on large numbers of letters.
Divide by the square of the seconds between letters. This gives you credit for speed. The use of the square gives you even more credit for aggresive times. A speed of 1.0 will have no effect on your score. A speed of 0.5 will give you four times your score. A speed of 2.0 will give you one fourth your score.
Multiply by 1,000. This converts your performance from sounding like a school grade to sounding like a video game score, which is cooler. A score of 59.275 is something you'd get on a bad English exam. A score of 59,275 is, "Dude, I almost broke 60K".
Real-life rationale for point system. In most real world situations, different types of errors have different difficulties of being fixed. That property of reality is reflected here by different point penalties for different kinds of mistakes. If the receiver adds extra letters, all the needed ones have at least been captured. The correction is a matter removing bad information, but not a loss of message information. Thus adding extra letters is only a half point loss. If the receiver gets a letter wrong, as least he knows that something should be there. This is defined as the average error case and given a one point loss. If the receiver drops a letter entirely, both the letter and the need for it are lost. Thus missing a letter is a one and a half point loss.
Value of typing skill unavoidable. This training tool aspires to be about the NPA. But since the answers must come through a keyboard of some type, typing skill matters and will impact your score. However, in most modern contexts, the receiver is often at a keyboard, so the value of typing skill can also be considered an integral part of the test.
Falling somewhat behind is okay.. There is no penalty for falling behind.If you are several letters behind and catch up, you will still get full credit. If the last letter is read, and it takes you a few more seconds to get them all typed in, you will still get full credit. There is a time limit as discussed next. If you fall so far behind that you hit the time limit, then you will lose points.
Time limit needed to prevent cheating.. After the last letter is said, and a few seconds pass, the input field will be locked. You should have plenty of time to type in the last few letters if you're catching up. But there is not enough time for various forms of cheating. Mainly this prevents recording the letters, then playing them back slowly.
Really bad answers may get inaccurate results.. Your answer is checked against the correct answer using the Levenshtein distance. This is a string matching algorithm known to be suprisingly effective at getting string matching back on track after rather bad errors. However, it is not infinite in its tolerance. If you make enough mistakes, even Levenshtein will be confused, and your score will plummet.
Deletion of history. Every score gets on the leaderboard. Bad scores drop off within a day. Progressively higher scores stay on progressively longer. Any score over 90 days old is purged.
Spaces between characters. When the question and answer strings appear on the leaderboard, they have a space every 25 characters. This is to allow the cells to wrap very long strings. If they are presented without spaces, it would make your browswer content very wide and cause horizontal scroll bars to appear.
Credit for audio files.. Great thanks to Collin at Easy Aviation English. Collin made his own phonetic alphabet page, and allowed us to reuse his audio files on QA76.His smooth airline pilot voice and clear articulation are a tremendous help and greatly appreciated.
Audio errors. In modern browsers, on a computer that is not too busy, and on a network with enough bandwidth, you should encounter no audio issues. If you do, run the test a few times with short strings to get your system to cache all the audio files. You should find this addresses the issues. If it persists, try a different brand of browser, ensure your computer is not too busy, and that you have enough bandwidth. If you flush your browser cache, you may find you have to repeat the process to cache all the audio files again.
Listening is the most critical skill. The best way to learn the NPA is by the approach taken on this page--listening and having to provide the letter. Why? Verbally is obviously better than in writing. Flash cards may be useful early on, but that's not how the NPA is used in reality. Seeing letters and having to speak them is definitely useful. But in real-world situations, if you're the one speaking them, you can set the pace. Your slow pace might have other implications for the work being done, but the receiver will not lose information. Hearing the names and having to know the letter--that is the most critical. In real-world situations, if you can't keep up, you lose information. If you lose enough information, you can make an error, or slow down the work even more dramatically than if you can't say them fast enough. Thus for any time you allocate to your NPA training, spend as much time as possible listening and capturing the letters--as is done on this page!