public function validateRequiredFields($postVars)
    {
        $requiredFields = $this->getRequiredFields($postVars['id']);
        $missingKeys = array();
        
        foreach ($requiredFields as $human => $keys) {
            if (!$this->hasRequiredValue($postVars, $keys)) {
                $missingKeys[] = $human;
            }
        }
        
        if (!empty($missingKeys)) {
            throw new GreenhouseApplicationException('Submission missing required answers for: ' . implode(', ', $missingKeys));
        }
        
        return true;
    }