I'm building on a map in Minecraft, where a player (myself for example) will press a button and his status changes into "The Player is ready for the game to begin".
So, press button ->
/scoreboard players set @p IsReady 1
Now I want to test if the player is ready, so
Redstone clock ->
The command block tells me that it can't find the player, but I'm there with a status of "IsReady 1".