The opinion
ROSENN, Circuit Judge,
dissenting.
I agree with the majority that under the special circumstances of this case the Interstate Commerce Commission (“ICC”) was justified in relaxing the standards of Connell Transport Co., Conversion Application, 95 M.C.C. 312 (1964), when it acted on Mack’s conversion application. I, too, believe that the ICC’s contribution to the dilemma in which Mack found itself warranted the application of a more lenient standard in determining whether Mack’s contract permit should be converted to a common carrier certificate. In my view, however, the ICC never defined the “lenient standard” that it purported to apply. That omission deprives this court of sufficient knowledge of the reasons underlying the Commission’s conclusions and prevents meaningful review. See Bowman Transportation, Inc. v. Arkansas-Best Freight System, Inc., 419 U.S. 281, 285-86 , 95 S.Ct. 438 , 42 L.Ed.2d 447 (1974). I am therefore constrained to dissent.
The Interstate Commerce Commission did not issue an opinion of its own in the instant case, but instead affirmed and adopted the decision of an administrative law judge. That decision (hereinafter referred to as “the Commission’s decision”) noted that under Fischbach Trucking Co., Common Carrier Application, 61 M.C.C. 539 (1953), carriers that seek conversion applications in order to correct mistakes to which the ICC has contributed have “certain equities in their favor.” Id. at 546. “Such carriers,” the Commission’s decision continued,
must still meet their full burden of proving public need for their operations as a common rather than contract carrier but the standards established are more lenient than usual. See T. T. Brooks Trucking Co., Inc., Extension —Akron, Ohio, 86 M.C.C. 667 (1961), in which conversion was authorized on the basis of partial shipper support and a general holding out; Eastern States Transp., Inc., Common Carrier Application, 105 M.C.C. 443 (1967); and Bankers Dispatch Corp., Conversion Application, 110 M.C.C. 294 (1969), in which the unusual contract to common carriage application was decided on analogous principles. Thus, conversion of applicants’ permit to a certificate is warranted.
This passage is the only discussion of the “lenient standard” governing Mack’s application that appears in the Commission’s decision.
The majority seems to conclude that the quoted passage constitutes an articulation of the standard applicable to conversion cases such as the instant one — the standard being “partial shipper support and a general holding out.” See Maj. Op. at 620. I cannot agree. Those eight words do not function as the definition of any standard for this case; rather, when read in context, they merely describe the Commission’s decision in T. T. Brooks Trucking Co., 86 M.C.C. 667 (1961). In transforming an account of a case into an announcement of a standard for adjudication, the majority ignores the essential requirement that an administrative agency lucidly state the reasons that support its action. 1 We have absolutely no *622 basis for determining whether the Commission considered “the relevant factors and whether there has been clear error of judgment.” Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 416 , 91 S.Ct. 814, 824 , 28 L.Ed.2d 136 (1971). The majority’s post hoc attempts to rationalize the actions of an administrative agency are not properly a part of the reviewing process. We may not rewrite an agency’s decision to provide the requisite reasoned basis for its conclusions. Bowman Transportation, Inc., supra, 419 U.S. at 285-86 , 95 S.Ct. 438 ; Atchison, T. & S. F. Ry. v. Wichita Board of Trade, 412 U.S. 800, 807 , 93 S.Ct. 2367 , 37 L.Ed.2d 350 (1973).
Even assuming arguendo that the quoted passage does define the “lenient standard,” I believe that the ostensible definition— “partial shipper support and a general holding out” — is critically deficient. Such a standard is, to my mind, hopelessly vague, requiring a reviewing court to speculate as to both the meaning and the application of the standard. Without additional explanation, those eight words provide no meaningful standard to guide this court in assessing whether Mack made the showing necessary to support its conversion application. See generally NLRB v. Armcor Industries, Inc., 535 F.2d 239, 245 (3d Cir. 1976).
Because I think that the Commission never defined the “lenient standard,” I am, of course, unable to say whether substantial evidence in the record as a whole supports the Commission’s .decision to approve Mack’s conversion to an extensive common carrier operation. Evidence cannot be weighed unless the measure be known. Still, I cannot help but observe that on any scale the evidence adduced in support, of Mack’s application was not heavy.
By the Commission’s own admission, carriers in Mack’s position “must still meet their full burden of proving public need for their operations as a common rather than contract carrier . . . .” To establish public need, Mack offered the testimony of fifteen shipper witnesses. Of those fifteen, at least thirteen, and possibly fourteen, were current users of Mack. Nine shippers seemed to say no more than that they were satisfied with the service they were receiving from Mack and wanted that service to continue. Two shippers suggested that Mack provided service that they could not obtain elsewhere. Three shippers seemed to have complaints with the service supplied by existing common carriers. One shipper testified that it did not currently use Mack, but that if the conversion application were granted, it would use Mack as a backup service for its private carriage operation.
Did this testimony establish public need for Mack’s operations as a common carrier? I reiterate that without knowing the standard governing what showing would suffice, I am unable to say. But the less-than-trenchant nature of the testimony offered surely underscores the need for a clear and complete articulation of that standard — a need that the ICC’s decision left unfulfilled.
' I would therefore remand the case to the Interstate Commerce Commission for a determination of the standard governing Mack’s conversion application, and for a reevaluation of the evidence in light of that standard.
. I recognize that “[a]n agency ‘may articulate the basis of its order by reference to other decisions.’ ” Atchison, T. & S. F. Ry. v. Wichita Bd. of Trade, 412 U.S. 800, 807 , 93 S.Ct. *622 2367, 2375 , 37 L.Ed.2d 350 (1973) (plurality opinion), quoting NLRB v. Metropolitan Life Ins. Co., 380 U.S. 438 , 443 n. 6, 85 S.Ct. 1061 , 13 L.Ed.2d 951 (1965). But it is not at all clear to me that this is what the ICC did in the instant case; I am unwilling to concede that the description of the standard applied in T. T. Brooks, without more, indicates, that the same standard was the one being applied in this case. I do not read Wichita Board of Trade, supra, as establishing that the mere citation of a case always provides sufficient explanation for an agency’s action. Such a canon would effectively eliminate the “simple but fundamental rule of administrative law” that an agency must set forth clearly the grounds on which it acted. SEC v. Chenery Corp., 332 U.S. 194, 196 , 67 S.Ct. 1575, 1577 , 91 L.Ed. 1995 (1947).