On Friday, the Army is expected to announce that it met only 75 percent of its recruiting goal for May, the fourth consecutive monthly shortfall in the number of new recruits sent to basic training. Just over 5,000 new recruits entered boot camp in May.

But the news could have appeared worse. Early last month, the Army, with no public notice, lowered its long-stated May goal to 6,700 recruits from 8,050. Compared with the original target, the Army achieved only 62.6 percent of its goal for the month.

Army officials defended the shift on Tuesday, saying it was not uncommon to change monthly goals at midyear. They said that the latest change reflected the reality that the Army was not going to meet its May goal, and that it made more sense to shift some of that quota to the summer months, traditionally a better season for recruiters to attract new high school graduates.

"We typically reallocate monthly goals during the course of the year," said Lt. Col. Bryan Hilferty, an Army spokesman, who said that the Army still expected to meet its overall annual goal of shipping 80,000 new recruits to boot camp. "The summer is relatively easier for recruiting."

Because of a series of recent incidents in which Army recruiters were found to be breaking or bending rules to meet their monthly quotas, two senior Army officials acknowledged that the shift in May could leave the impression that the Army was playing "a shell game" with its recruiting figures, shifting its goals to make the numbers look better than they are. But the two officials, who were speaking on condition of anonymity because the monthly figures have not yet been made public, said that impression was not justified.

The Pentagon has delayed until Friday the public release of May recruiting figures for all the armed services, a decision some military officials say is an effort to minimize what has become a drumbeat of bad news for the Army and the Marine Corps at the beginning of each month. Previously, each service, as well as the National Guard and the Reserve, released their monthly figures on different days at the start of each month, with each gaining some media attention.

But a Pentagon spokesman, Bryan Whitman, said, "Any large organization with data that is of public interest would want to present it in a way that makes sense and is complete for the entire organization."

The Army's figures for May put the service about 8,300 soldiers behind its projected year-to-date number of enlistees sent to basic training by now. "The trend line is going against them," said Senator Jack Reed, a Rhode Island Democrat on the Armed Services Committee.

The Army has tried to reverse the trend by adding 1,000 recruiters since last September, starting a new advertising campaign, offering selected enlistment bonuses of more than $20,000 and pairing returning veterans from Iraq and Afghanistan with recruiters to attract soldiers.

Harvey Perritt, a spokesman for the Army's Training and Doctrine Command, said the original May quota was set months ago when officials expected an early surge in recruiting. That did not happen. By April, only 50 percent of the training positions at the Army's five major training centers were filled, down from 92 percent in the corresponding period a year earlier, Mr. Perritt said. The Army then reallocated some of the May quota.

"The shifting of the goal suggests to me that the Army is aggressively working the problem and not passively sitting by and letting the mission slip away," said Beth J. Asch, a senior economist at the RAND Corporation.

Two recruiters in the New York area, insisting on anonymity because the Army has ordered all recruiters not to talk to reporters, said their mission for June had not been changed, nor had the goals for July, August and September.

One of the recruiters said he doubted that the summer would yield more recruits than the spring. "The summer is supposed to be big, but I don't think it's going to happen," he said. "I don't see much interest among the high school seniors."

To help offset the recruiting shortfalls, the Army is also trying to keep more soldiers. A memorandum from the Army's top personnel officer last month outlined a plan to reduce attrition among first-term enlistees by 1 percent, and retain 3,000 soldiers.

The memorandum, first reported last week by The Wall Street Journal, requires the approval of more senior-level brigade commanders, instead of battalion commanders, to discharge soldiers for pregnancy, drug or alcohol abuse, or poor fitness.

Colonel Hilferty said the Army was ahead of this year's goal to re-enlist 64,162 soldiers, which is 8,000 more than last year's target. Aided by tax-free re-enlistment bonuses, virtually every Army unit that has served or is serving in Iraq or Afghanistan has exceeded its re-enlistment goals in the past two years.

Damien Cave contributed reporting from New York for this article.