private boolean isKnownValue(int field, String value) {
        
        if (value.isEmpty()) {
            return true
;        }
                
        if (isAgeField(field)) {
            if (!isValidNumber(value)) {
                return false;
            }
            else {
                return true;
            }
        }

        if (dictionaries == null || dictionaries.size() <= field) {
            return true;
        }
        
        TreeSet<String> dictionary = dictionaries.get(field);
        if (dictionary == null || dictionary.isEmpty()) {
            return true;
        }
        
        return dictionaries.get(field).contains(value);
        
    }