Development by cause and effect
Analysing causes is a very common strategy in thinking as well as writing; consequently, you often see writing that analyses causes. For example, an editorial in a newspaper may analyse why the government cut money from a particular program or why a particular law will be good or bad for the society. An essay could focus on why the stock market crash of 1929 occurred, or on why a scientific experiment succeeded or failed.
Your thesis sentence for an essay analysing causes cannot cover each specific cause your paper will mention, but it should indicate major causes specifically and minor causes generally. An essay analysing the causes of the disappearance of the family farm could have this thesis:
Although there are many reasons for the disappearance of the family farm, competition from large agri-business conglomerates makes it difficult for a small farm to prosper.
This essay might mention the high cost of farm machinery, the tendency of fewer young people to pursue farming careers, or the controls on crop prices, noting that these have also contributed to a shrinking number of family farms. However, most of the essay would focus on the competition from agri-business.
Some essays of causal analysis focus on the cause(s) of something, others analyse only the effect(s); still others discuss both. Regardless of which type you are writing, here are a couple of rules you may want to stick to:
Present a reasonable statement
If your thesis makes dogmatic, unsupportable claims (e.g. medicare will lead to a complete collapse of quality medical treatment) or overly broad assertions (e.g. boredom is the cause of alcoholism among housewives), you won't convince your reader. Limit or qualify your thesis whenever necessary by using such phrases as "may be," "a contributing factor," "one of the main reasons," "two important factors," and so on.
Avoid the post hoc fallacy
This error in logic (from the Latin phrase post hoc ergo propter hoc, meaning after this, therefore because of this) results when we mistake a temporal connection for a causal relationship -or, in other words, when we assume that because one event follows another in time, the first event caused the second.
Avoid circular logic
Often causal essays seem to chase their own tails when they include such circular statements as "There are not enough parking spaces for students on campus because there are too many cars." Such a statement merely presents a second half that restates what is already implied in the first half. A revision might say, "There aren't enough parking spaces for students on campus because the parking permits are not distributed fairly." This kind of assertion can be argued specifically and effectively; the other is a dead end.