Academic, laboratory, and commercial studies have a common difficulty. In order to obtain valid conclusions about the specific factor, or quality, that is the focus of the study all other relevant factors must be kept constant. These constants are called control variables. If there are unidentified variables which might affect measurements or there are relevant variables that cannot be sufficiently taken into account, the measurements of the target factor do not necessarily support any conclusion. The measurements might not be due to the factors under study.
This is true for studies on disease (possible environmental aspects -- known or unknown, genetic background, emotional and mental attitudes), social mediation techniques (lead contamination or other physical harmful aspects, social networks, personal history, etc.), sports, business success, or any other area in which a specific outcome is to be measured and quantified.
It is currently popular for some to indicate that a person's outcome (physical, economic, education, social, business, ...) is due solely to their ability and their efforts. So, in this case, there are variables -- ability and efforts -- and measured outcomes (in the physical arena, educational achievements, business success, etc.) The harder you work and the more able you are, the better will be your results. And that is very likely true -- though luck (occurrences that you have no direct, or indirect, control over) will always play a part in the results.
Once again, an individual, depending on luck, will be able to do better if they have greater ability and work harder.
That conclusion is not possible when you compare two different individuals. If one person is just as able and works just as hard as another then they should be able to do as well? This is faulty logic -- there are too many variables that are not under control.
It is similar to comparing two racers -- one of which is one foot from the finish line and has no obstacles and the other is a mile from the finish line with hurdles, landmines, broken glass, and dangerous animals attacking them along the way.
What types of variables are not under control?
- Family income -- can they afford training/help/schooling?
- Family interaction and encouragement -- do they have encouragement, "cheerleaders", role models?
- Peer values -- is the goal of value to friends and associates?
- Biases and prejudices -- does everyone around them give them equal opportunities to achieve the goal?
- Physical health and environment -- have they had sufficient, and proper, food growing up? Have there been any inescapable toxic substances in their environment?
- Neighborhood -- includes peer values but also is it safe around their neighborhood? Do they have the opportunities needed to prepare themselves to achieve the goal?
- Factors X, Y, and Z -- like any other study, there are possibly other factors that vary between two people that are important in the achievement of the goal.
It is possible to have a statistical conclusion when you compare equally varied pools of people. If you have large enough pools, the control variables will tend to average out between the two groups. But not for two individuals.
People have achieved, and continue to achieve, fantastic things no matter how much the deck has been dealt against them. Working hard is always a positive factor. Striving to do one's best and to continue to improve must help in the journey to the goal.
But comparing the effort, and abilities, needed to achieve a goal between two people just isn't possible if you cannot keep those control variables constant.
