A census determines size of the population and other demographic information. A national census is done once every 10 years to determine amounts of money and services to allocate to different locations pertaining to population size. There are numerous ways to conduct a population census including through the mail, in person and over the phone. Each of these methods has advantages and disadvantages.
The most common method of conducting a population census is by sending a survey through the mail, where it can be filled out and returned through the mail. The advantages of this method are that the person filling out the survey can do it on their own time and return it via mail at no cost. This method is also fairly cheap compared to the other methods. This method also has disadvantages, one being that there is no way of guaranteeing that everyone receives a copy of the survey. There is also the chance that the person who received the survey will not fill it out and return it. Through mail also takes time, you have to wait for it to get to the person, for them to fill it out and then wait for it to get returned through the mail.
Census takers can go door-to-door to those places where surveys have not been returned. By going to a person's home, the chances of getting the survey filled out increase dramatically. However, the biggest problem with going door-to-door is the cost. The government has to pay census takers to go door-to-door, which is much more expensive then sending mail at a bulk rate. Time is also a factor in going door-to-door because it takes time for census takers to find houses, arrive when someone is home and conduct interviews. Additionally, door-to-door census takers have personal safety and security concerns to take into account as they go about their jobs.
Over the Phone
If the government does not receive your census survey in the mail after a few weeks, census collectors make phone calls before they send people door-to-door. This method is not as cheap as sending the survey through the mail, but it is much less expensive than going door-to-door. This method can be effective if you reach the person at home. All the person has to do is answer a few questions quickly, and it saves them the time of filling out the survey themselves. If you cannot reach the person over the phone, it is necessary to send people door-to-door. Also, many people don't have landlines and use cell phone numbers instead, which are not listed.
In the Future
In 2020 the United States will conduct another census with the hopes that people will be able to go online and fill out the survey. This method will be useful for those among the population who are computer savvy. The other methods will still need to be used for those of us who do not have Internet access and for those who do not fill out the survey online or in the mail.