SAS PROGRAMS USED IN CALCULATION OF
AIR NETWORK PREMIUM FACTORS
This library reference shows the calculation of the commercial cost equivalents and pound-mile distributions by airclass for the Eagle Network and the Western Network (WNET). It underlies the testimony of witness Pickett (USPS-T-19), which explains the reasons for these calculations. The output of these calculations feeds into witness Meehan’s Cost Segment 14B Workpapers (USPS-T-11). The premium costs are treated as incremental in the testimony of witness Kay (USPS-T-23). The material in this library reference revises and/or updates materials presented in LR-H-81 and LR-H-85 in Docket No. R97-1. This library reference was prepared by PricewaterhouseCoopers LLP.
PROGRAM OVERVIEW

PROGRAM DOCUMENTATION

Purpose:Calculation of Eagle Network (ANET) and Western Network (WNET) air transportation pound-miles by ACT Tag and commercial equivalent costs

Program:TRACSSMN.BY98.ENCRYPT.PGMS.CNTL(NET*)

III.Requirements of computer analysis relied upon

A.A general description of the program that includes:

  1. Objectives of the program: The objectives of the programs are to develop commercial equivalent costs for operating the Eagle and Western networks; and, create a pound-mile distribution of mail across ACT Tag codes for the Eagle and Western networks.
  1. Processing tasks performed: Each program reads in and merges two text files, then modifies the data to create a final SAS data set (13 in all).
  1. Methods and procedures employed: See attached program listing.
  1. A listing of the input and output data: See attached pages describing names and sizes of input and output data.
  1. A listing of the source codes: See attached programs and accompanying execution logs.

B.For all input data:

  1. Designation of all sources of such data:

TRACSSMN.Z.ACSS.AP**98.TEXT are 13 text files (one for each AP in FY 1998) containing air payment data.

TRACSSMN.Z.LATF04Q.PQ*98.FLAT.TEXT are four (4) text files (one for each quarter in FY 1998) containing facility latitude and longitude information that has been downloaded from the National Traffic Management System (NTMS) and encrypted for use in these programs.

  1. Explanation of any modifications to such data made for use in the program: None.

C.Definitions of all input and output variables or sets of variables: See attached description of input and output data.

D.A description of input and output data file organization: See attached description of input and output data.

E.A machine-readable copy of all data bases: All final edited databases are available on accompanying CD-ROM.

F.For all source codes, documentation sufficiently comprehensive and detailed to satisfy generally accepted software documentation standards appropriate to the type of program and to its intended use in the proceedings: See attached program and documentation.

G.The source program in machine-readable form: Included on CD-ROM as four (4) programs named NET*.SAS (one for each quarter in FY 1998).

H.All pertinent operating system and programming language manuals: SAS User's Guide: Basics

I.If the requested program is user interactive, a representative sample program run, together with any explanation necessary to illustrate the response sequence: N/A

J."Canned" Statistical Packages: SAS Version 6.09

K.Special requirements for computer simulations models offered in evidence or relied upon as support for other evidence: N/A

Program:TRACSSMN.BY98.ENCRYPT.PGMS.CNTL(NET*)

Inputs:TRACSSMN.Z.ACSS.AP**98.TEXT

TRACSSMN.Z.ACSS.AP**98.TEXT are 13 text files (one for each AP in FY 1998) containing air payment data from the Air Contract Support System (ACSS).

APNumber of observationsNumber of variables

11,011,19929

2971,35629

3977,84829

4910,19529

5934,56929

6943,57129

7913,30429

8911,84729

9880,62329

10843,78529

11827,55129

12829,41029

13776,26129

TRACSSMN.Z.LATF04Q.PQ*98.FLAT.TEXT

TRACSSMN.Z.LATF04Q.PQ*98.FLAT.TEXT are four (4) text files (one for each quarter in FY 1998) containing facility latitude and longitude information that has been downloaded from the National Traffic Management System (NTMS) and encrypted for use in these programs.

PQNumber of observationsNumber of variables

150,0175

250,0175

350,0175

450,0175

Outputs:TRACSSMN.Z.PREMIUM.AP**98.SASDATA(AIRODS)

TRACSSMN.Z.PREMIUM.AP**98.SASDATA contains the SAS data set AIRODS, which contains average haul and commercial equivalent cost data for commercial origin-destination pairs, as based on air payment files for each AP in FY 1998.

APNumber of observationsNumber of variables

115,3144

215,3434

315,3414

415,4814

514,9244

614,9154

714,8654

814,8034

914,6204

1014,4194

1114,2614

1214,2044

1313,9344

Variables read in from TRACSSMN.Z.ACSS.AP**98.TEXT:

FYFiscal year in which the flight occurred

WEEKWeek in which the flight occurred

SUM_TYPEComponent type code to which the movement costs accrue

PAY_TYPEPayment type

FACAOrigin of the first leg of the dispatch

RTAAirline carrying mail on the first leg of the dispatch

TRIPAFlight number of the first leg of the dispatch

PAYDATEDate of the air movement

FINLDESTDestination of the last leg of the dispatch

LEG_INDTotal number of legs (1, 2 or 3) on the dispatch

FACBOrigin of the second leg of the dispatch

RTBAirline carrying mail on the second leg of the dispatch

TRIPBFlight number of the second leg of the dispatch

FACCOrigin of the third leg of the dispatch

RTCAirline carrying mail on the third leg of the dispatch

TRIPCFlight number of the third leg of the dispatch

REC_TYPERecord type

REC_SEQRecord sequence

PAYMILEGreat Circle Distance (GCD) miles for the first leg of the dispatch, on which payment is based

FC_WTGross weight (in pounds) of the First-Class (‘F’) items scanned for dispatch

EX_WTGross weight (in pounds) of Express (‘X’) items scanned for the dispatch

PR_WTGross weight (in pounds) of Priority (‘P’) items scanned for the dispatch

SDAY_WTGross weight (in pounds) of Same Day (‘S’) items scanned for the dispatch

PAL_WTGross weight (in pounds) of the Parcel Airlift (PAL) items scanned for the dispatch

OTHERWTGross weight (in pounds) of items that were scanned under a code other that those listed above or that were not scanned at all (‘O’)

LS_WTTotal weight (in pounds) of all loose (i.e., noncontainerized) items on the dispatch

CONT_WTTotal weight of all containerized mail on the dispatch

LSAMTDUETotal amount paid for loose sack items on the dispatch

CTAMTDUETotal amount paid for containerized items on the dispatch

Variables read from TRACSSMN.Z.LATF04Q.PQ*98.FLAT.TEXT:

CFacility code

LATDEGFacility latitude (degrees)

LATMINFacility latitude (minutes)

LONDEGFacility longitude (degrees)

LONMINFacility longitude (minutes)

Variables contained in TRACSSMN.Z.PREMIUM.AP**98.SASDATA(AIRODS):

ORIGINOriginating facility of scanned mail on a flight

FINLDESTFinal destination facility of scanned mail on a flight

AVGHAULAverage haul (in miles) for all commercial air dispatches in the AP with the same origin and final destination

UNITCOSTAverage cost per pound for all commercial air dispatches in the AP with the same origin and final destination

Specific functions performed in the programs:

  • ACSS is a macro that reads prepares air payment data for each specified AP. (Lines 8-408)
  • Reads in raw air payment data from TRACSSMN.Z.ACSS.AP**98.TEXT. Reads in cost variables (LSAMTDUE and CTAMTDUE) for commercial air dispatches and sets cost variables to zero for non-commercial air dispatches. (Lines 10-51)
  • Retains only valid records by verifying that loose sack pounds (LS_WT) equals the sum of the various mail class pounds (FC_WT, EX_WT, PR_WT, SDAY_WT, PAL_WT and OT_WT); the sum of loose sack and containerized mail pounds is greater than zero; and, dispatch records contain one, two or three legs. Creates variables for total dispatch pounds (WT) and total dispatch cost (COST). Combines Express and Same Day pounds into single variable (EX_WT) and containerized mail and Parcel Airlift mail into single variable (CONT_WT). (Lines 53-61)
  • Distinguishes between commercial and network air dispatch records. Retains only valid payment records, deleting any records indicating neither commercial nor network air dispatches. (Lines 63-65)
  • Removes duplicate records and collapses data to create one record per unique dispatch. (Lines 72-78)
  • Creates separate data sets that represent commercial and network air records, respectively. (Lines 85-90)
  • Prepares commercial air payment records so that dispatches with multiple legs are represented by a single record (that is, data represents one record for each complete commercial air dispatch, rather than one record for each separate dispatch leg). Uses dispatch leg data to verify data for consistency within each given dispatch. (Lines 98-139)
  • Checks for volume mismatches between the different legs of similar dispatch records. (Lines 141-164)
  • Verifies that commercial dispatch records are not missing pieces of routing data. (Lines 168-179)
  • Sums total cost, pounds and pound-miles for each origin-destination pair found among commercial records. Also calculates commercial cost per pound and average haul for each origin-destination pair. (Lines 189-202)
  • Verifies that network dispatch records are not missing pieces of routing data. (Lines 214-319)
  • Prepares network air payment records to build universe of origin-destination pairs. Retains only first-leg dispatch records – unlike in commercial records (in which cost and payment mileage data must be retained for each leg), all necessary routing and weight information for network air dispatches can be found in the first-leg dispatches. Separates records into two data sets – NET, which contains records indicating only Eagle and/or Western air carriers, and OTHERNET, which contains air carriers other than those found on the Eagle or Western networks. (Lines 223-229)
  • Checks network dispatch records in the data set NET for inter-line transportation between the Eagle and Western networks. (Lines 233-235)
  • Uses Eagle/Western inter-line dispatch records to create separate records for Eagle and Western network transportation. (Lines 242-257)
  • Checks records in the data set OTHERNET (i.e., that included at least one non-Eagle/non-Western leg). Splits records appropriately to retain Eagle and Western legs only. (Lines 262-286)
  • Checks records in the data set OTHERNET for inter-line transportation between the Eagle and Western networks. (Lines 290-297)
  • Recombines all network records into a single data set. (Lines 301-305)
  • Renames network hub facility codes to match up with commercial record facility codes. (Lines 309-313)
  • Sums airclass pounds by network and origin-destination pairs. (Lines 317-319)
  • Appends commercial costs per pound and average haul data to network origin-destination pairs to develop commercial equivalent costs and pound-miles for the Eagle and Western networks. (Lines 327-341)
  • Calculates Great Circle Distance miles (GCD) for network origin-destination pairs for which commercial equivalent costs are not available. (Lines 351-383)
  • Uses GCD estimation to calculate pound-miles for origin-destination pairs for which commercial equivalent costs are not available. Uses Air System (ASYS) line-haul and terminal handling cost component rates to calculate commercial equivalent costs for these origin-destination pairs. (Lines 387-391)
  • Recombines all network records into a single data set. Sums pounds and pound-miles by network. (Lines 398-404)
  • Combines data from each AP within the quarter to calculate and present commercial air data and network premium totals for the quarter. (Lines 415-416)
  • Sums and prints quarterly commercial air totals for pounds, pound-miles and costs. (Lines 418-422)
  • Sums and prints quarterly network air totals for pounds, pound-miles and costs by airclass. (Lines 424-430)
  • Calculates final airclass pound-miles by distributing containerized pound-miles across the four ACT Tag identifiers. (Lines 435-439)
  • Prints final pound-miles by airclass. (Lines 441-442)

LR-I-55: SAS Programs Used in Calculation of Air Network Premium Factors – 1