This is an essay topic from one of the MGMAT CAT tests.
I have written the essay under timed session.

Background: Japanese (non-native)
I basically went blank on the actual test because I hardly put any time preparing for AWA and I am going to retake it on mid-nov.
(retaking not because of AWA only... Got a dissappointing 580 after 2.5months of study)

ESSAY QUESTION:
The following appeared as part of a campaign statement for Velazquez, who is seeking election as alderman in the town of Barchester:

“Under Police Commissioner Draco, the city of Spartanburg began jailing people for committing petty crimes such as littering, shoplifting, and spraying graffiti. Criminals in Spartanburg must have understood that lawlessness would no longer be tolerated, because the following year Spartanburg saw a 20% drop in violent crimes such as homicide. Our town should learn from Commissioner Draco’s success, and begin a large-scale crackdown on petty crime.”

Discuss how well reasoned you find this argument. In your discussion be sure to analyze the line of reasoning and the use of evidence in the argument. For example, you may need to consider what questionable assumptions underlie the thinking and what alternative explanations or counterexamples might weaken the conclusion. You can also discuss what sort of evidence would strengthen or refute the argument, what changes in the argument would make it more logically sound, and what, if anything, would help you better evaluate its conclusion.

YOUR RESPONSE:
There is a gap in the line of reasoning in the Velazquez's statement. He claimes that because commissioner Darco started jailing people for committing petty crimes , it can be concluded that the campaign was successful in reducing the rate of violent crimes.

First, Velazquez addressed two different categories of crimes and reasoned that because of some actions taken for one category, the other category must have had an effect. It is an assumption on which no clear relation other than "awareness" has been shown between the two category. The Violent and petty crimes may or may not be related, but the relation is not stated nor can be concluded.

Second, the reason for the 20% drop in violent crimes is not presented, but assumed. The 20% drop in violent crimes may be because of many reasons for instance, if very little violent crimes are committed at any given time, 1 or 2 violent crime difference can set a big change in the rate of violent crimes. for example if only 2 violent crimes were committed last year and only 1 violent crime was committed this year, the rate of drop would be 50%! So, it would be more convincing to show a drop in number of violent crimes as opposed to rate of violent crimes.

Finally, the statement can be strengthened by streamlining the cause and effect. For example, The violent crime rate has decreased because the penalty for violent crimes was increased by 50% longer imprisonment. This show a straight forward link between the cause and effect as opposed to relating a cause that may or may not have an effect on the other.