user618: Chess players often say that in a given tournament they were "in good shape", or the opposite. One tournament goes well, another goes horribly wrong. One can also sometimes feel that your head is working well, and tactics are calculated more easily than usual. There are days when it feels the opposite. Is there a test that can tell me "how well is my head working today"? The goal is not to measure relative skill of several players, but rather to measure the day-to-day condition of a single player, whose overall chess experience and strength is roughly stable.

user2637: From what I've learnt, the only way to find out how good you are today is by finding out how good you are today. IOW, there is no substitute for playing some games of chess to find out how good you are.
Matthew:out

user2429: I do not know of any such standardized chess test. 
But here are some general questions you should ask yourself. The "correct" answers are provided in parenthesis. If you answer all correctly, you should be in good shape. 
Physical Preparation


Have I had enough sleep? (Yes)
Have I had enough food to give me sufficient energy for the game? (Yes)
Have I over-eaten? (No)
Do I feel stressed out? (No)
Is my body in good shape without any kind of aches? (Yes)
Are my eyes relaxed? (Yes) 
Do I feel sick? (No)
Do I feel fresh? (Yes)
Do I feel tired? (No)


Mental Preparation


Is anything bothering me? (e.g. angry exchange with co-worker) (No)
Is there something else on my mind that can be a distraction (e.g. date with girlfriend)? (No)
Do I have a headache? (No)
Am I under the influence of alcohol or any such other drug? (No)


Chess Preparation


Have I made good opening preparation for the game? (Yes)
Am I afraid of my opponent? (No)
Have I practiced chess tactics recently? (Yes)
Am I confident that I can play well? (Yes)


If you answered all "correctly", you're in really good shape. 
P.S. (I'll add more to the list as and when I remember)

618: <p>Chess players often say that in a given tournament they were "in good shape", or the opposite. One tournament goes well, another goes horribly wrong. One can also sometimes feel that your head is working well, and tactics are calculated more easily than usual. There are days when it feels the opposite. Is there a test that can tell me "how well is my head working today"? The goal is not to measure relative skill of several players, but rather to measure the day-to-day condition of a single player, whose overall chess experience and strength is roughly stable.</p>
 2637: <p>From what I've learnt, the only way to find out how good you are today is by finding out how good you are today. IOW, there is no substitute for playing some games of chess to find out how good you are.</p>

<p>Matthew:out</p>
 2429: <p>I do not know of any such standardized chess test. </p>

<p>But here are some general questions you should ask yourself. The "correct" answers are provided in parenthesis. If you answer all correctly, you should be in good shape. </p>

<p><strong>Physical Preparation</strong></p>

<blockquote>
  <ol>
  <li>Have I had enough sleep? (Yes)</li>
  <li>Have I had enough food to give me sufficient energy for the game? (Yes)</li>
  <li>Have I over-eaten? (No)</li>
  <li>Do I feel stressed out? (No)</li>
  <li>Is my body in good shape without any kind of aches? (Yes)</li>
  <li>Are my eyes relaxed? (Yes) </li>
  <li>Do I feel sick? (No)</li>
  <li>Do I feel fresh? (Yes)</li>
  <li>Do I feel tired? (No)</li>
  </ol>
</blockquote>

<p><strong>Mental Preparation</strong></p>

<blockquote>
  <ol>
  <li>Is anything bothering me? (e.g. angry exchange with co-worker) (No)</li>
  <li>Is there something else on my mind that can be a distraction (e.g. date with girlfriend)? (No)</li>
  <li>Do I have a headache? (No)</li>
  <li>Am I under the influence of alcohol or any such other drug? (No)</li>
  </ol>
</blockquote>

<p><strong>Chess Preparation</strong></p>

<blockquote>
  <ol>
  <li>Have I made good opening preparation for the game? (Yes)</li>
  <li>Am I afraid of my opponent? (No)</li>
  <li>Have I practiced chess tactics recently? (Yes)</li>
  <li>Am I confident that I can play well? (Yes)</li>
  </ol>
</blockquote>

<p>If you answered all "correctly", you're in really good shape. </p>

<p>P.S. (I'll add more to the list as and when I remember)</p>
