Before deciding on what terms they will offer you on a home loan (which they base on their "risk"), mortgage lenders want to know two things about you: your ability to pay back the home loan, and your willingness to pay back the home loan. For the first, they look at your income-to-debt obligation ratio. For your willingness to pay back the home loan, they consult your credit score.

The most widely used credit scores are FICO scores, which were developed by Fair Isaac & Company, Inc. (and they're named after their inventor!). Your FWIO score is between 350 (high risk) and 850 (low risk).

Credit scores only consider the information contained in your credit profile. They do not consider your income, savings, down payment amount, or demographic factors like gender, race, nationality or marital status. In fact, the fact they don't consider demographic factors is why they were invented in the first place. "Profiling" was as dirty a word when FICO scores were invented as it is now. Credit scoring was developed as a way to consider only what was relevant to somebody's willingness to repay a loan.

Past delinquencies, derogatory payment behavior, bankruptcy and foreclosure, current debt level, length of credit history, types of credit and number of inquiries are all considered in credit scores. Your score considers both positive and negative information in your credit report. Late payments will lower your score, but establishing or reestablishing a good track record of making payments on time will raise your score.

Different portions of your credit history are given different weights. Thirty-five percent of your FICO score is based on your specific payment history. Thirty percent is your current level of indebtedness. Fifteen percent each is the time your open credit has been in use (ten year old accounts are good, six month old ones aren't as good) and types of credit available to you (installment loans such as student loans, car loans, etc. versus revolving and debit accounts like credit cards). Finally, five percent is pursuit of new credit -- credit scores requested.

Your credit report must contain at least one account which has been open for six months or more, and at least one account that has been updated in the past six months for you to get a credit score. This ensures that there is enough information in your report to generate an accurate score. If you do not meet the minimum criteria for getting a score, you may need to establish a credit history prior to applying for a mortgage.

In today's increasingly automated society, it should come as no surprise that when you apply for a mortgage, your ability to pay can be reduced to a single number. All the years you've been paying your mortgage, car payments, and credit card bills can be analyzed, sliced, diced, spindled and mutilated into a single indicator of whether you're likely to meet your future obligations.

All three of the major credit reporting agencies (Equifax, Experian and TransUnion) use a slightly different system to arrive at a score. The best known is called the FICO score, based on a model developed by Fair Isaac and Company (hence the name) and used by Experian. Equifax's model is called BEACON, while TransUnion uses EMPIRICA. While each of the models considers a range of data available in your credit report, the primary factors are:

Each of these, and other items, are assigned a value and a weight. The results are added up and distilled into a single number. FICO scores range from 300 to 800, with higher being better. Typical home buyers likely find their scores falling between 600 and 800.

FICO scores are used for more than just determining whether or not you qualify for a mortgage. Higher scores indicate you are a better credit risk, and thus may qualify for a better mortgage rate.

What can you do about your FICO score?

Unfortunately, nothing quickly. Since the score is based on a lifetime of credit history, it is difficult to make a significant change in the number with quick fixes. The most important thing is to know your FICO score and to ensure that your credit history is correct. Conveniently, Fair Isaac has created a web site (www.myFICO.com) that let's you do just that. For a reasonable fee, you can quickly get your FICO score from all three reporting agencies, along with your credit report. Also available is some helpful information and tools that help you analyze what actions might have the greatest impact on your FICO score. Each of the credit services offers similar services on their web sites: www.equifax.com, www.experian.com, and www.transunion.com.

It's virtually impossible to change your score in the time between when most people decide to buy a home or refinance their mortgage and when they apply. So the short answer is, you really can't "on the spot." But there are strategies you can live with to make sure when you apply for a loan your score is as high as possible.

Make sure that the information each of the three credit reporting bureaus has on you is consistent and up to date. Order a copy of your credit report about once a year, and dispute any inaccuracies.

Note: Theoretically, if a series of credit reports is requested on your behalf during a limited amount of time, your score goes down until time passes without any inquiries. Changes in the law though have made "consumer-originating" credit report requests not count so much. Also, a series of requests in relation to getting a mortgage or car loan is not treated the same as a number of credit card requests in a limited time. This is because the credit bureaus, and lenders, realize that people request their own credit reports to keep up with what's on them, and smart consumers shop around for the best mortgage and car loans.

Unsolicited credit card solicitations in the mail don't count against your credit report, so don't worry.

The two main components of your credit score are your payment history and the amounts you owe. Bankruptcy filings and foreclosures, which can stay on your credit report for as many as 10 years, can significantly lower your score. It's never a good idea to take on more credit than you can handle.

Late payments work against you. It's extremely important to pay bills on time, even if it's only the monthly payment.

Dont "max out" your credit lines. Since the size of the balance on your open accounts is a factor, lower balances are better.

It's said that by carefully managing your credit, it's possible to add as much as 50 points per year to your score.

If you encounter a mistake?

If you do encounter a mistake on your credit report, several steps need to be taken to correct the matter:

1. The first thing to do is get a copy of your credit report from each of the three major CRAs: Equifax, http://www.equifax.com; Experian, http://www.experian.com; and TransUnion, http://www.tuc.com.

2 In a written letter, tell the CRA what information you believe to be inaccurate. Include copies (not originals) of documents that support your position. Provide your complete name and address, identify each item in your report you dispute, and request deletion or correction. Be sure to make copies of your dispute letter and enclosures.

3. Send your letter by certified mail, return receipt requested, so you can document what the CRA received.

4. The FCRA mandates that all CRAs reinvestigate the items in question usually within 30 days unless they consider your dispute frivolous. They also must forward all relevant data you provide about the dispute to the credit card company. After the credit card company receives notice of a dispute from the CRA, it must investigate, review all relevant information and report the results to the CRA.

5. If the disputed information is found to be inaccurate, the credit card company must notify all nationwide CRAs so they can correct this information in your file. Disputed information that cannot be verified must be deleted from your file.

6. When the reinvestigation is complete, the CRA must give you the written results and a free copy of your report if the dispute results in a change. If an item is changed or removed, the CRA cannot put the disputed information back in your file unless the credit card company verifies its accuracy and completeness, and the CRA gives you a written notice that includes the name, address, and phone number of the credit card company.

7. In addition to the CRA, you should also write to the credit card company about the error. Again, include copies of documents that support your dispute. If you are correct meaning the information you disputed is found inaccurate the credit card company cannot use it again. Further, at your request, the CRA must send notices of corrections to anyone who received your report in the past six months.