spot–check 
/ˈspɑ:tˌtʃɛk/ verb
spot–checks; spot–checked; spot–check·ing /ˈspɑ:tˌtʃɛk/ verb : to check (something) quickly for problems especially by looking at a few things or people in a group [+ obj] ▪ He spot-checked the data for errors. ▪ Police spot-checked cars at the border. [no obj] — often + for ▪ She spot-checked for errors.
