Exhibit 99.1

THE ADVISORY BOARD COMPANY REPORTS
RESULTS FOR QUARTER ENDED MARCH 31, 2011

Company Reports Quarterly Revenue Growth of 22%, Contract Value Growth of 19%, and Member
Renewal Rate of 91%; Announces Two New Programs

WASHINGTON, D.C. — (May 5, 2011) — The Advisory Board Company (NASDAQ: ABCO) today announced financial results for the quarter ended March 31, 2011, the fourth quarter of its 2011 fiscal year. Revenue for the quarter increased 21.8% to $77.2 million, from $63.4 million in the quarter ended March 31, 2010. Contract value increased 18.7% to $310.1 million as of March 31, 2011, up from $261.1 million as of March 31, 2010. For the quarter ended March 31, 2011, net income was $5.1 million, or $0.30 per diluted share, compared to net income of $5.1 million, or $0.32 per diluted share, for the prior quarter. For the quarter ended March 31, 2011, adjusted net income, non-GAAP earnings per diluted share and adjusted EBITDA, all of which are non-GAAP financial measures, were $7.4 million, $0.44 per diluted share and $12.0 million, respectively.  For the quarter ended March 31, 2010, adjusted net income, non-GAAP earnings per diluted share, and adjusted EBITDA were $7.6 million, $0.48 per diluted share, and $12.9 million, respectively.

For the fiscal year ended March 31, 2011, revenue increased 21.3% to $290.2 million, from $239.3 million for the fiscal year ended March 31, 2010. Net income was $18.5 million, or $1.13 per diluted share, for the fiscal year ended March 31, 2011, compared to net income of $11.4 million, or $0.73 per diluted share, for the prior fiscal year. For the fiscal year ended March 31, 2011, adjusted net income, non-GAAP earnings per diluted share, and adjusted EBITDA were $28.4 million, $1.73 per diluted share, and $48.0 million, respectively.  For the fiscal year ended March 31, 2010, adjusted net income, non-GAAP earnings per diluted share, and adjusted EBITDA were $26.1 million, $1.66 per diluted share, and $43.8 million, respectively.

Robert Musslewhite, Chief Executive Officer of The Advisory Board Company, commented, “We closed the quarter and the fiscal year with strong performance and are off to a good start against our calendar 2011 objectives.  The continued change and complexity in the markets we serve is driving a sustained, urgent need for our products and services, as evidenced by both our 22% revenue growth for the quarter and also by our 19% growth in contract value over last year at this time.  Our outstanding 91% overall renewal rate, the highest since 2005, reflects both excellent product quality and measurable impact for our membership, which has grown nearly 9% and stands at 3,243 institutions.”

Mr. Musslewhite continued, “I am pleased to announce today the launch of two new programs.  The first, Crimson Care Registry, builds on our successful Crimson platform to provide new point-of-care patient registry tools based on proven clinical care guidelines.  Crimson Care Registry helps physicians improve patient care by providing actionable and customizable prompts during care delivery, capturing clinical information, and aligning physician quality across the ambulatory setting.  We anticipate that Crimson Care Registry will be an essential tool under value-based payment structures and are confident that the addition of the product to the Crimson portfolio will provide tremendous value to all members of the program.

“Our second new program, the Clinical Denials Prevention Program, hardwires a best practice approach to patient precertification, automating the authorization, retrieval, and submission process in order to prevent related denials.  Because 54% of denied claims are attributed to improper precertification—errors that result in a 3-5% loss of net revenue for most hospitals—improving these processes has a significant bottom line impact.  Through software that leverages both hospital and payer data sets, as well as a proprietary, robust, comprehensive authorization rules engine, the Clinical Denials Prevention Program aids hospitals in the creation of an accurate and efficient precertification process.”

Mr. Musslewhite concluded, “In today’s dynamic market, our members are asking that we develop deeper, more comprehensive ways to partner with them as the health care market evolves.  We have responded and have seen strong growth across all parts of the portfolio.  With our software-based memberships now comprising more than 50% of our total contract value and serving over 1,000 participating organizations, it is clear that our members see tremendous value in our expanded capabilities.  We continue to see numerous opportunities ahead of us to partner more deeply with them, and we are confident in the future prospects of our business in doing so.” 

Share Repurchase

During the three months ended March 31, 2011, the Company repurchased 35,973 shares of its common stock at a total cost of approximately $1.8 million. As of March 31, 2011, the Company had repurchased 7,520,671 shares of its common stock at a total cost of approximately $316.3 million.

Outlook for Calendar Year 2011

The Company reaffirmed its previously announced calendar year 2011 guidance for revenue, non-GAAP earnings per diluted share, and adjusted EBITDA. For calendar year 2011, the Company expects revenue to be in a range of approximately $318 million to $326 million, adjusted EBITDA to be in a range of approximately $56 million to $60 million, and non-GAAP earnings per diluted share of approximately $1.85 to $2.00. For calendar year 2011 the Company expects share-based compensation expense to be approximately $10 million, and amortization from acquisition-related intangible assets to be approximately $4.5 million. For the fiscal year ending March 31, 2012, the Company expects an effective tax rate of approximately 36.5% to 37.5%.

Non-GAAP Financial Measures

This press release and the accompanying tables present information about adjusted EBITDA, adjusted net income, and non-GAAP earnings per diluted share, which are non-GAAP financial measures provided as a complement to the results provided in accordance with accounting principles generally accepted in the United States of America (“GAAP”).

We define our non-GAAP financial measures as described below. The term “adjusted EBITDA” refers to a financial measure that we define as earnings before other income, net, which includes interest income and foreign currency losses and gains; income taxes; depreciation and amortization; amortization of acquisition-related intangibles and capitalized software included in cost of services; non-cash charges associated with the write-off of capitalized software and the cancellation of certain stock options that occurred in the quarter ended September 30, 2009; costs associated with the acquisitions of Concuity Services Inc. (“Concuity”) and Cielo MedSolutions LLC (“Cielo”) that occurred in the quarters ended March 31, 2010 and 2011, respectively; share-based compensation expense; and fair value adjustments made to the Company’s acquisition-related earn out liabilities. The term “adjusted net income” refers to net income excluding the net of tax effect of non-cash charges associated with the write-off of capitalized software and the cancellation of certain stock options; share-based compensation expense; amortization of acquisition-related intangibles; costs associated with the acquisitions of Concuity and Cielo; and fair value adjustments made to the Company’s acquisition-related earn out liabilities. The term “non-GAAP earnings per diluted share” refers to net income per share excluding the net of tax effect of non-cash charges associated with the write-off of capitalized software and the cancellation of certain stock options; share-based compensation expense; amortization of acquisition-related intangibles; costs associated with the acquisitions of Concuity and Cielo; and fair value adjustments made to the Company’s acquisition-related earn out liabilities.

The foregoing non-GAAP measures may be calculated differently from similarly titled measures used by other companies, which limits their usefulness as comparative measures, and should be considered in addition to financial measures prepared in accordance with GAAP, but should not be considered a substitute for, or superior to, GAAP measures or results as indicators of performance. We use these non-GAAP financial measures for internal budgeting and other managerial purposes because they enable the Company’s management to evaluate projected operating results on a basis that allows for comparability without regard to changes arising from applicable tax rates, variability in interest income and foreign currency exchange rates, periodic costs of certain capitalized tangible and intangible assets, share-based compensation expense and certain non-cash and special charges.

There are limitations associated with these non-GAAP financial measures as indicators of performance, including that they do not reflect all changes in applicable tax rates, foreign currency exchange rates, share-based compensation expense or the periodic costs of certain capitalized tangible and intangible assets used in generating revenue in our business.

A reconciliation of the foregoing historical non-GAAP financial measures to the most directly comparable historical GAAP financial measures is provided below for each of the periods indicated. It is not practicable to provide a reconciliation of forecasted adjusted EBITDA and forecasted non-GAAP earnings per diluted share to the most directly comparable GAAP financial measures because certain items required for the forecast of such GAAP financial measures cannot reasonably be estimated or predicted at this time.

Web and Conference Call Information

As previously announced, the Company will hold a conference call to discuss its fourth quarter performance this evening, May 5, 2011 at 5:30 p.m. Eastern Time. The conference call will be available via live web cast on the Company’s web site at www.advisoryboardcompany.com/IR. To participate by telephone, the dial-in number is 866.700.6979 and the access code is 39077402. Participants are advised to dial-in at least five minutes prior to the call to register. The web cast will be archived for seven days from 8:30 p.m. Eastern Time on Thursday, May 5, until 8:30 p.m. Eastern Time on Thursday, May 12, 2011.

About The Advisory Board Company

The Advisory Board Company provides best practices research and analysis, business intelligence and software tools, and installation support and management and advisory services to approximately 3,200 organizations, including hospitals, health systems, pharmaceutical and biotech companies, health care insurers, medical device companies, colleges, universities, and other educational institutions. Members of each program typically are charged a fixed fee and have access to an integrated set of services that may include best practice research studies, executive education seminars, customized research briefs, web-based access to the program’s content database, and software tools.

Forward-Looking Statements

This news release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These statements, including the Company’s expectations regarding its revenue, adjusted EBITDA and non-GAAP earnings per diluted share for calendar year 2011 and its effective tax rate for fiscal year 2012, are based on information available to the Company as of May 5, 2011, the date of this news release, as well as the Company’s current projections, forecasts, and assumptions, and involve risks and uncertainties. You are hereby cautioned that these statements may be affected by certain factors, including those set forth below. Consequently, actual operations and results may differ materially from the results discussed or implied in the forward-looking statements, and reported results should not be considered as an indication of future performance. Factors that could cause actual results to differ materially from those indicated or implied by forward-looking statements include, among others, changes in the financial condition of the health care industry, our dependence on renewal of membership-based services, the need to attract new business and retain current members and qualified personnel, new product development, competition, risks associated with our software tools and installation support tools, our ability to license technology from third parties, risks associated with anticipating market trends, industry consolidation, variability of quarterly operating results, possible volatility in the Company’s stock price, and various factors related to income and other taxes, including whether the District of Columbia withdraws the Company’s status as a Qualified High-Tech Company, as well as those risks and uncertainties described in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2010 and also disclosed from time to time in its subsequent reports on Form 10-Q and Form 8-K, which are available on the Company’s website at www.advisoryboardcompany.com/IR and at the Securities and Exchange Commission’s website at www.sec.gov. Additional information will also be set forth in the Company’s report on Form 10-K for the fiscal year ended March 31, 2011, which will be filed with the Securities and Exchange Commission in June 2011.

Accordingly, readers are cautioned not to place undue reliance on forward-looking statements made in this news release, which speak only as of the date of this news release, and the Company does not undertake to update these statements, whether as a result of circumstances or events that arise after the date they are made, new information, or otherwise.

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THE ADVISORY BOARD COMPANY
UNAUDITED CONSOLIDATED STATEMENTS OF INCOME
AND OTHER OPERATING STATISTICS
(In thousands, except per share data)

THE ADVISORY BOARD COMPANY
CONSOLIDATED BALANCE SHEETS
(In thousands)

THE ADVISORY BOARD COMPANY
UNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS
(In thousands)