Odds of a green card visa lottery winner actually getting a green card visa [source: Examiner]

Many DV lottery sites estimate the chances of winning the lottery based on the overall chances of getting selected. These odds are dependent on the number of entrants and other factors. For DV-2011, we previously estimated that approximately 17 million will register for the calendar year 2009 lottery from eligible countries.
If accurate, then the overall chances of receiving a winning letter from the U.S. State Department are 100,000 in 17 million, or 0.6 percent (one in 170). However, the odds of getting a visa are 50% of that, since only 50,000 of the initial 100,000 are actually issued a visa. This means the overall odds are not 1 in 170, but closer to 1 in 340. But is this really true?

Once all applications are received by the cutoff date and the Department of State performs its lottery, 100,000 winners are chosen at random by their computers. A maximum of 50,000 will eventually obtain immigrant visas or green card visa. The remaining 50,000 initially chosen will not qualify for the visas for various reasons. What this also means is that there will not be a sufficient number of visas for all of those who are initially selected. And all applicants who are selected will be informed promptly by postal mail (not e-mail) of their place on the list, or they can determine their winning status online.

Each month the Department of State determines how many visas will be issued (numbers permitting) to those applicants who are ready for issuance either by having completed the appropriate forms and submitting documents within the U.S., via CIS, or abroad to U.S. consular offices.

The Department of State will assign each application to one of six geographic regions of the world: 1) Africa, 2) Asia, 3) Europe, 4) North America, 5) Oceania, and 6) South America, Mexico, Central America and the Caribbean. Of course, some of these regions contain countries that are ineligible for a particular year’s DV lottery.
When selected, each application will be assigned an application number. This number will determine where on the list an applicant stands within his/her country and region of origin. For some applicants, it is nothing more than an identification characteristic; for others it will actually determine when and if they can receive an immigrant visa or green card visa, as we explain in the next article.

[source: Examiner]