Some Members of Congress who landed in Roll Call’s “Have-Not Caucus” last year appear to have improved their lot since, chipping away at the personal loans, credit card balances and other liabilities that placed them on the poorest list during 2010.

A preliminary review of the annual disclosure forms that lawmakers filed for 2011, released to the public on Thursday, show that about half of the 10 lawmakers whom Roll Call calculated as being the least well-off Members of Congress reported a greater minimum net worth than in the year before.

The 10 on last year’s list were Democratic Reps. Alcee Hastings (Fla.), Rubén Hinojosa (Texas), Barbara Lee (Calif.), Laura Richardson (Calif.), Jerrold Nadler (N.Y.), Linda Sánchez (Calif.) and Sanford Bishop (Ga.) and Republican Reps. John Sullivan (Okla.), Sean Duffy (Wis.) and Kristi Noem (S.D.).

Each year since 1990, Roll Call has reviewed the financial disclosures of all Representatives and Senators to determine the 50 richest Members of Congress for an annual report, which is forthcoming.

Roll Call looks at the poorest in Congress to get a sense of how lawmakers are faring as the country recovers from the recession. Many of the richest have not yet filed their financial disclosures after being granted extensions. At least 24 on last year’s wealthiest list received such an extension, including seven of the top 10, according to the website LegiStorm.

Though the annual disclosures provide detailed information about lawmakers’ finances, including stock holdings, financial transactions and other investments, it is hard to ascertain an individual’s wealth because of the type of information that must be provided.

Assets that must be reported, for example, include the year-end values of bank accounts, stocks and rental properties but not of personal residences and federal retirement savings accounts. A lawmaker’s debts, including student loans, outstanding legal bills, credit card balances and, for the first time this year, mortgages on personal residences, are reported if they exceed $10,000 at any time during the year, even if they are paid off before the year ends.

Calculating a lawmaker’s wealth is further complicated by the fact that assets and liabilities are reported within ranges. Roll Call adds the minimum value of the assets and subtracts the total minimum value of all liabilities to arrive at a minimum net worth.

Lee was one Member on Roll Call’s list of the poorest who managed to improve her lot. The California Democrat’s reported minimum net worth increased from negative $763,000 in 2010 to at least $12,011 in 2011, largely due to the repayment of a personal loan of at least $15,001 and a mortgage on an Oakland, Calif., property of at least $1,000,001 that were previously listed as liabilities.

It is expected that a provision in the recently passed Stop Trading on Congressional Knowledge Act requiring lawmakers to report mortgages on personal residences as liabilities — but not the residences as assets — will cause the reported minimum net worth of many to dip in this year’s batch of disclosure reports, even if they have repaid other debts.

Noem, for example, paid off at least $20,002 in credit card debt, and the minimum value of a family-owned insurance business increased from $350,001 to at least $500,001. That would have vastly increased her minimum net worth had a mortgage of $250,001 to $500,000 not been reported as a liability.

Outstanding legal bills continue to prove costly for the have-nots, increasing the likelihood that they will remain among the least wealthy in Congress.

Hastings was Roll Call’s poorest Member of Congress last year, with a negative net worth of about $2.13 million. That figure appears to have changed little in 2011, largely due to outstanding legal debt that could be as high as $7.3 million.

The decades-old legal bills were incurred in the 1980s, when Hastings was defending charges that he had taken bribes as a federal judge. A jury acquitted Hastings, but he was ultimately impeached and convicted by Congress. The financial remnants of the probe will likely land the Florida lawmaker among the poorest in Congress on this year’s list.

Richardson appears to have likewise not paid down debts owed to two law firms that together surpass $150,000.

Kate Ackley, Janie Lorber and Adriel Bettelheim contributed to this report.

Correction: June 17, 2012

An earlier version of this story misstated Roll Call’s calculation of the minimum net worth of Rep. Barbara Lee (D-Calif.). It is at least $12,011, according to Roll Call’s formula.