At the beginning of the year, we asked ProPublica Illinois readers what they wanted to know about how we do our work. Thoughtful, challenging questions have been rolling in ever since, and we’ve been answering them in an occasional series of columns. In this dispatch, data reporter Sandhya Kambhampati answers a question about the Freedom of Information Act.

What is the Freedom of Information Act (FOIA)? What kind of documents can you request using the FOIA? Have there been any attacks on the FOIA in recent years? If so, what are they? —Rachel Lietz

The Freedom of Information Act (FOIA) allows anyone — not just journalists — to request records from the government or any public agency. Getting records through FOIA is crucial, and it has been a boon for reporters. It helps us keep a close eye on what the government is doing and to hold people in power accountable.

Say you got sick after eating at a hot dog stand at Wrigley Field. Well, you can file a FOIA for the restaurant’s inspection reports from the Chicago Department of Health. Interested in what route garbage trucks take? Request a map from the Chicago Department of Streets and Sanitation.

Other documents you can request include, but are not limited to*: budgets, PowerPoint presentations and audio/visual training materials, calendars, meeting minutes and email.

*See what I did there — helpful language to use if you want to file your own FOIA.

Here are a few examples of ProPublica Illinois stories that FOIA helped make possible:

There are all sorts of unexpected, even fun, ways to use FOIA. WBEZ reporter Elliott Ramos found out which Chicago neighborhood had the most block parties. He requested applications for block parties from the Chicago Department of Transportation. Curious about the most popular dog names? Block Club Chicago took a look at the dogs of the Windy City, using pet application data from City Clerk’s office.

You can request data in different formats: Excel (xlsx), text files (.txt), or comma-separated values (CSV) format or databases (SQL, Access), although agencies love to keep us on our feet by printing out Excel files and sending the requested records back in a PDF form. PDFs are the worst because you have to convert them back to Excel to calculate data or enter it by hand. I frequently file requests with government agencies to get data to combine with other datasets readily available online, such as matching census data on income to parking tickets. I’ve written previously about the thousands of requests I’ve sent out and some tips I have for the long, sometimes painful process that comes along with sending record requests.

To be successful, it helps to understand the various federal, state and local FOIA laws. Under FOIA, agencies are not required to “create” records for you, and they must already possess the materials you want. This is where it’s helpful to be specific so the agency can easily determine what records you’re requesting. There’s a little science to writing a request and figuring out the specificity a given agency requires. It also helps to have a conversation with a person at an agency before you send off your request, so you know the right words to use. Some agencies have certain words that trigger a denial. For example, “everything” will probably get you a rejection.

Some exemptions allow government agencies to withhold documents. These include law enforcement records that could interfere with an open case, trade secrets, preliminary drafts or personal information, such as Social Security numbers that, if disclosed, would be an invasion of someone’s privacy. An agency can also label someone a “recurrent requester” if they submit 50 or more requests to the same public body in one year, 15 requests in 30 days, or seven within a 7-day period, which enables the agency to turn down their requests. (This label cannot be used for reporters.)

As valuable as FOIA is for reporters, agencies often resist releasing records. Some agencies, it seems, routinely deny requests in hopes the requester will simply go away. Others say a request will take an exceedingly long time to fulfill. And in what has become a common refrain, agencies will claim a request is unduly burdensome. That means the burden on the public body to produce the records outweighs the public’s interest in the information.

According to an analysis done by the Associated Press, the federal government withheld or censored records more often last year than at any other time over the past decade. The AP also found the federal government spent $40.6 million last year in legal fees to withhold files.

In Illinois, there’s an appeals process if you believe your request has been incorrectly denied. You can request review from the Illinois Attorney General’s Public Access Counselor (PAC), which helps resolve issues involving open records requests.

Last year, there were an average of 324 requests for review per month, according to the Public Access Counselor, giving some indication how common denials are throughout the state. The PAC issues a ruling on each request for review but some of these decisions are non-binding, so the agencies don’t have to follow them.

As journalists — and as citizens — we need FOIA to hold our government and public bodies accountable. We’ll keep filing requests here at ProPublica Illinois and, to paraphrase the Beastie Boys, you should fight for your right to FOIA, too.

Do you have a question about journalism? Send it to us at illinois@propublica.org.