The Commonwealth appeals from the denial of its motion for judgment notwithstanding the verdict or in the alternative for a new trial. We transferred the case from the Appeals Court to this court on our own initiative. We reverse the judgment entered in the Superior Court and order that judgment be entered for the Commonwealth.

The plaintiffs brought this action against the Commonwealth under G. L. c. 258 (1994 ed.) the Massachusetts Tort Claims Act for the wrongful death of their decedent Ruth T. Burroughs. The decedent was fatally injured in a motor vehicle accident that involved an automobile driven by an off duty member of the Massachusetts National Guard Robert LaCasse. On the night of the accident LaCasse had been served alcoholic beverages by Michael Morgante another off duty member of the Massachusetts National Guard at the Braintree National Guard armory and was operating the automobile while under the influence of that alcohol.

The plaintiffs claimed at the jury trial that the Commonwealth through its employees was negligent and its negligence caused the decedent's death. The Court instructed the jury on two theories of negligence. He told the jury that if Morgante was acting within the scope of his employment as a public employee while serving LaCasse the alcoholic beverages and was negligent the jury could find the Commonwealth vicariously liable. The Court also instructed the jury that if the National Guard had control over the alcohol served at the armory on the night of the accident the jury could also find the Commonwealth liable as a social host.

The Court instructed the jury to answer two questions: (1) "Was the defendant Commonwealth of Massachusetts by its employee(s) negligent?" (2) "Was the defendant Commonwealth of Massachusetts' negligence a substantial contributing cause of the death of the plaintiffs' decedent Ruth T. Burroughs?" The jury answered both questions "Yes." The jury did not specify nor were they asked to specify whether they found the Commonwealth negligent under the vicarious liability or under the so-called "social host " theory. Because there was insufficient evidence to support a finding either that Morgante was acting within the scope of his employment by the Commonwealth when he served the alcoholic beverages to LaCasse or that the Commonwealth through one or more of its employees in the course of employment negligently permitted the availability of alcohol to LaCasse at the armory on the night of the accident we reverse the judgment.

In measuring the legal sufficiency of the evidence to warrant a finding that Morgante was acting in the scope of his employment while serving liquor to LaCasse or that the Commonwealth through its employees was negligent in its control of the alcohol served at the armory the test is whether "anywhere in the evidence from whatever source derived any combination of circumstances could be found from which a reasonable inference could be drawn in favor of the plaintiff." Poirier v. Plymouth 374 Mass. 206 212 372 N.E.2d 212 (1978) quoting Raunela v. Hertz Corp. 361 Mass. 341 343 280 N.E.2d 179 (1972). In order for an inference to be reasonable it must be based on "probabilities rather than possibilities" and must not be the result of "mere speculation and conjecture." Alholm v. Wareham 371 Mass. 621 627 358 N.E.2d 788 (1976).

Viewing the evidence in the light most favorable to the plaintiffs the evidence would have warranted the jury in finding the following facts. On January 23 1985 Michael Morgante attended a training meeting at the National Guard armory in Braintree. Morgante was a part-time member of the Massachusetts National Guard and attended the meeting in his capacity as a platoon sergeant. Morgante was not ordered to attend the meeting but he did so in order to prepare for a drill assembly on the following weekend. At about 7 P.M. National Guard officers dismissed the meeting and Morgante proceeded to open the armory's noncommissioned officers (NCO) club. The NCO club was a room located in the armory and was furnished with a bar stools tables a pool table and a dart board. All the furnishings were provided by individual members of the National Guard. The club sold alcoholic beverages from a bar. The beverages were the property of the club. *fn3 The National Guard itself and therefore the Commonwealth did not own the beverages.

Morgante served as the NCO club's bartender on the night of the accident as he had on other evenings. He was not required to be at the armory at that time and his bartending was voluntary and without compensation. One of the Guard members at the NCO club that evening was nineteen year old Robert LaCasse. LaCasse had not attended the training meeting that day but had been informed at a prior training assembly that there would be alcoholic bar service at the armory on the evening of January 23.

Over a span of two and one-half hours Morgante served LaCasse eight to ten twelve-ounce "rum and cokes" and at least one "boilermaker " which consists of a shot of liquor in a glass of beer. LaCasse became visibly intoxicated. When he left the NCO club at around 9:30 P.M. he had a blood alcohol level of approximately 0.15 per cent. Around midnight without having consumed any additional alcohol LaCasse caused the accident resulting in the death of the plaintiffs' decedent.

In 1986 in Wang Lab. Inc. v. Business Incentives Inc. 398 Mass. 854 859 501 N.E.2d 1163 (1986) we set forth the factors relevant to scope of employment determinations bearing on the imposition of vicarious liability on employers for the tortuous conduct of their employees as follows:

"Conduct of an agent is within the scope of employment if it is of the kind he is employed to perform Douglas v. Holyoke Mach. Co. 233 Mass. 573 576 124 N.E.478 (1919); if it occurs substantially within the authorized time and space limits Vallavanti v. Armour & Co. 260 Mass. 417 419-420 157 N.E.527 (1927); and if it is motivated at least in part by a purpose to serve the employer Donahue v. Vorenberg 227 Mass. 1 5 116 N.E.246 (1917); McKeever v. Ratcliffe 218 Mass. 17 20 105 N.E.552 (1914) . See Restatement (Second) of Agency Sec. (1958)."

"The scope of employment test asks the question: is this the kind of thing that in a general way employees of this kind do in employment of this kind" (emphasis in original). Kansallis Fin. Ltd. v. Fern 421 Mass. 659 666 659 N.E.2d 731 (1996).

We conclude that the evidence would not have warranted the jury in finding that while bartending Morgante was carrying out a duty imposed on him by his employment. General Laws c. 258 SEC. provides in material part that "public employers shall be liable for injury or loss of property or personal injury or death caused by the negligent or wrongful act or omission of any public employee while acting within the scope of his office or employment in the same manner and to the same extent as a private individual under like circumstances " A National Guard member is "acting within the scope of his office or employment" if he is "acting in the performance of any lawfully ordered military duty." G. L. c. 258 SEC. For all that appears in the evidence Morgante's bartending was nothing other than a way of relaxing and socializing that he performed without compensation and that was neither explicitly nor implicitly ordered or even requested by his superiors. The evidence would not have warranted a finding that Morgante's "conduct . . . [was] of the kind he [was] employed to perform" or that it was "motivated at least in part by a purpose to serve the [Commonwealth] " Wang Lab. Inc. v. Business Incentives Inc. supra at 859. The evidence would not have warranted a finding that his conduct bartending at the NCO club was "the kind of thing that in a general way" part-time National Guardsmen do. *fn4 See Kansallis Fin. Ltd. v. Fern supra.

We turn now to the question whether the evidence would have warranted a finding of the Commonwealth's negligence under the "social host" theory of tort liability. In McGuiggan v. New England Tel. & Tel. Co. 398 Mass. 152 162 496 N.E.2d 141 (1986) we stated:

"We would recognize a social host's liability to a person injured by an intoxicated guest's negligent operation of a motor vehicle where a social host who knew or should have known that his guest was drunk nevertheless gave him or permitted him to take an alcoholic drink and thereafter because of his intoxication the guest negligently operated a motor vehicle causing the third person's injury."

Thereafter in numerous social host cases we have held that a social host is not liable to a person injured as a result of a guest's excessive consumption of alcohol that was not owned or furnished by the host. See Mosko v. Raytheon Co. 416 Mass. 395 622 N.E.2d 1066 (1993); Cremins v. Clancy 415 Mass. 289 612 N.E.2d 1183 (1993); Ulwick v. DeChristopher 411 Mass. 401 582 N.E.2d 954 (1991). We reasoned that as a practical matter a social host ordinarily lacks the ability effectively to control his or her guests' consumption of alcohol not owned or furnished by the host. See Mosko supra at 402; Cremins supra at 294; Ulwick supra at 406.

It may well be that the rule and rationale of the cited cases should not apply to this case where the host's ability to control the supply of liquor provided by others would appear to be significantly greater than the ability of the social hosts in those cases. We need not decide that issue however because the plaintiffs have not identified and we have not discovered sufficient evidence in the instant case to warrant a finding that anyone while acting within the scope of his or her employment by the National Guard (i.e. Commonwealth) either by action or inaction failed to exercise that degree of care vigilance and forethought that an ordinarily prudent person would have exercised to ensure that no underage or intoxicated person would have access to alcoholic drinks while at the NCO club. As we have discussed above Morgante was not shown to have been such a person. The plaintiffs have not identified and we have not found evidence to show that in allowing Morgante to tend bar or in any other way those in authority at the armory failed to take reasonable precautions to prevent that which occurred and gave rise to this litigation.

Because there was insufficient evidence to warrant a finding for the plaintiffs on either theory of their case we reverse the judgment and order the entry of judgment for the Commonwealth.