I believe there are many forms of intelligence, some more important than others are. A person may be very smart but when it comes to subjects like math and science, but when it comes to English and writing they may not know much about it. Also, some people may not do very well in school but can fix almost anything that you put in front of them.
Often times those who are smart in school subject lack the common sense needed to survive outside of work or school although that is not always the case. Others who may very intelligent when it comes to common sense and making the right decision on the street lack the wisdom need in school or work. This is a critical part of survival and I believe common sense is needed just as much as anything else.
There are those people who are naturally smart, who grasp concepts well, and do not need to study much at all to do well. There are others who need to work hard to do well. They need to study and concepts do not come as easily to them as others. Are they not considered intelligent because of this? Also many people may be very intelligent yet they are either lazy or uninterested, therefore their natural mental ability never is shown.
Many cultures have their own opinion of intelligence. If you are born and brought up as an Indian, to them intelligence comes with age and strength. If you can hunt well and survive on you own then you are considered intelligent, you are not given a written test and judged buy the scores. Many other cultures also have their own definition of intelligence too. Social status also has a very big impact on people perspective of your intelligence. Upper to middle class people not only have a better chance of getting a good education, but are thought of as more intelligent because they have money. Lower-middle to lower class people do not have all the opportunities that the others do and are also perceived as unintelligent because of their lack of money and those opportunities.
Judging people on their level of intelligence, mental ability, and level of success through tests and careers gives you a very poor judge of character. I do not agree that intelligence can be measured at all. To me it is not only how smart you are, but also your attitude, who you are as a person, and the decisions you make in life. Your intelligence should not only be graded through a test but rather on how you live your life.