At the time, I thought he was a little nuts. But over the years I have come to understand the wisdom of this approach to a first level of creative review, and I have shared it with many other people. (So a tip-of-the-hat to all the boss wisdom we don't appreciate at the time. Perhaps it's like the wisdom of our moms and dads, which we don't fully recognize it until we are out on our own.)
Now, Don was old school and the desktop revolution had not yet invaded his office. In other words, he had no computer. So the squint test was conducted with literal printouts and a big office. Today you can get the same result by zooming out on your sales asset on-screen.
Physical or electronic, the squint test tells you a number of things very quickly:
1. Is piece visually pleasing? Is there a good balance of copy and negative space? Are the margins sufficient? Does the piece feel crowded or unfinished?
2. Are the colors balanced? Does one color shout while the others whisper? Is there harmony in the palette Are the saturation levels too similar so that the colors appear muddy?
3. Where does your eye land first? Is that the most important point? Are there two seemingly equal areas of interest? Is that desirable for this piece?
4. If the piece is for a projected presentation, how will it look from the very back of a large room? If the piece is for a billboard, what shapes will drivers see before content clicks into focus?
If you are deciding among several layout options, print out tiny "squint" version (where you can grasp the layout but not read the words) and as a few coworkers to comment on them. The strongest layout will become apparent.
After you're happy with the squint test, of course you'll need get into the nitty-gritty of the copy and design. But Don's point, and now my point, is that if the squint test fails, it doesn't matter how tight the copy is or how creative the graphics. If your don't make it past the squint, neither will your audience.