Despite Harvard’s endowment returns lagging behind its peers in recent years, a 2015 internal review leaked to Bloomberg News suggests that the school’s investment office had set performance targets low enough to ensure high pay for some of its managers.

Conducted by the consulting firm McKinsey & Company and reported by Bloomberg last Thursday, the review provided a candid analysis of Harvard’s investment office. The consulting firm’s findings underscored the challenges of setting appropriate benchmarks to assess the performance of university endowments such as Harvard’s and Yale’s, because of their investments in assets whose value cannot be measured as frequently as publicly traded stocks and bonds.

The review analyzed Harvard’s performance between June 2009 and June 2014.

“It has become conventional for investment managers to use some kind of index to see how they are doing in relative terms,” said William Jarvis ’77, executive director of the Commonfund Institute, an institutional-investment advisory firm. “The challenge comes when you have less liquid portfolios with assets like real estate and private equity — then you have to start creating less conventional benchmarks that might cause some disagreement.”

Since assuming their roles in 1985, University Chief Investment Officer David Swensen and Senior Director of Investments Dean Takahashi have pioneered a strategy that places a significant amount of the University’s endowment in less conventional assets. Yale’s annual endowment update for fiscal 2015 indicates that more than half of the endowment’s then-$25.6 billion market value was allocated in illiquid asset classes, including natural resources, real estate and venture capital.

While such investments have delivered high returns for the endowment — the University’s venture capital investments have earned about 93 percent on average annually between fiscal 1995 and fiscal 2015 — Yale faces the same challenge as its peers in assessing the relative performance of such investment strategies.

At Yale, the Investments Office regularly reviews asset class benchmarks. Any changes recommended are put before the University’s investment committee, which oversees the office’s activities.

“It is very difficult to select an appropriate benchmark in certain asset classes,” said economics professor and Nobel laureate Robert Shiller. “There is not always a clear best standard, and endowment managers can justifiably reach different conclusions about what is appropriate in their individual cases.”

Hedge fund manager and School of Management finance professor Roger Ibbotson said that even the best benchmarks can only provide a limited assessment of annual performance over the long duration of a market cycle.

“Because these are investments designed to perform over market cycles that last many years, assessing performance in relation to annual benchmarks will not provide an accurate picture in most cases,” Ibbotson said. “Determining annual compensation packages based on outperforming benchmarks becomes quite a challenge then.”

Ibbotson also noted that the structure of an investment office like Harvard’s — which employs both external and internal fund managers — can exacerbate the problems associated with benchmark selection. Compensation packages for internal employees can be much higher in Harvard’s “hybrid” model of hiring internal and external managers.

Unlike Yale’s endowment, a vast majority of which is invested by external money managers, much of Harvard’s $36 billion endowment is managed internally. Many employees of Harvard’s office received large salaries for having outperformed internally designated benchmarks in the years under review by McKinsey.

Tax filings from fiscal 2009 to fiscal 2014 show that Harvard paid its investment office’s top 11 internal managers nearly a quarter of $1 billion in the five-year time period. At Yale, compensation for the top investment office employees across the University over the same period did not cross $100 million.

Part of the difference between Yale’s and Harvard’s compensation payouts can be attributed to Yale paying a greater proportion of costly fees associated with investment management to external managers, according to Ibbotson. But the McKinsey report also noted that Harvard had less demanding benchmarks for asset performance than Yale, Princeton or Stanford.

While Harvard had beaten its benchmarks for the report’s five-year period by 1 percentage point, McKinsey analysts noted in their report that if Harvard’s performance had been measured by the same benchmarks in use by Stanford’s investment office, Harvard would have underperformed by 0.5 percentage points.

Correction, Jan. 19: An earlier version of this article incorrectly compared endowment performance benchmarks at Yale and Harvard.