diff --git a/parser/gradeLoader.go b/parser/gradeLoader.go
index aad3004..2d37f64 100644
--- a/parser/gradeLoader.go
+++ b/parser/gradeLoader.go
@@ -10,6 +10,8 @@ import (
 	"strings"
 )
 
+var grades = []string{"A+", "A", "A-", "B+", "B", "B-", "C+", "C", "C-", "D+", "D", "D-", "F", "W", "P", "CR", "NC", "I"}
+
 func loadGrades(csvDir string) map[string]map[string][]int {
 
 	// MAP[SEMESTER] -> MAP[SUBJECT + NUMBER + SECTION] -> GRADE DISTRIBUTION
@@ -73,68 +75,48 @@ func csvToMap(csvFile *os.File, logFile *os.File) map[string][]int {
 	if err != nil {
 		log.Panicf("Error parsing %s: %s", csvFile.Name(), err.Error())
 	}
-	// look for the subject column and w column
-	subjectCol := -1
-	catalogNumberCol := -1
-	sectionCol := -1
-	wCol := -1
-	aPlusCol := -1
-
-	headerRow := records[0]
-
-	for j := 0; j < len(headerRow); j++ {
-		switch {
-		case headerRow[j] == "Subject":
-			subjectCol = j
-		case headerRow[j] == "Catalog Number" || headerRow[j] == "Catalog Nbr":
-			catalogNumberCol = j
-		case headerRow[j] == "Section":
-			sectionCol = j
-		case headerRow[j] == "W" || headerRow[j] == "Total W" || headerRow[j] == "W Total":
-			wCol = j
-		case headerRow[j] == "A+":
-			aPlusCol = j
-		}
-		if wCol == -1 || subjectCol == -1 || catalogNumberCol == -1 || sectionCol == -1 || aPlusCol == -1 {
-			continue
-		} else {
-			break
+
+	indexMap := make(map[string]int)
+
+	for j, col := range records[0] {
+		switch col {
+		case "Catalog Number", "Catalog Nbr":
+			indexMap["Catalog Number"] = j
+		case "W", "Total W", "W Total":
+			indexMap["W"] = j
+		default:
+			indexMap[col] = j
 		}
 	}
 
-	if wCol == -1 {
-		logFile.WriteString("could not find W column")
-		//log.Panicf("could not find W column")
-	}
-	if sectionCol == -1 {
-		logFile.WriteString("could not find Section column")
-		log.Panicf("could not find Section column")
-	}
-	if subjectCol == -1 {
-		logFile.WriteString("could not find Subject column")
-		log.Panicf("could not find Subject column")
-	}
-	if catalogNumberCol == -1 {
-		logFile.WriteString("could not find catalog # column")
-		log.Panicf("could not find catalog # column")
+	// required columns
+	for _, name := range []string{"Section", "Subject", "Catalog Number", "A+"} {
+		if _, ok := indexMap[name]; !ok {
+			logFile.WriteString(fmt.Sprintf("could not find %s column", name))
+			log.Panicf("could not find %s column", name)
+		}
 	}
-	if aPlusCol == -1 {
-		logFile.WriteString("could not find A+ column")
-		log.Panicf("could not find A+ column")
+
+	// optional columns
+	for _, name := range []string{"W", "P", "CR", "NC", "I"} {
+		if _, ok := indexMap[name]; !ok {
+			logFile.WriteString(fmt.Sprintf("could not find %s column\n", name))
+		}
 	}
 
+	sectionCol := indexMap["Section"]
+	subjectCol := indexMap["Subject"]
+	catalogNumberCol := indexMap["Catalog Number"]
+
 	distroMap := make(map[string][]int)
 
-	for _, record := range records {
+	for _, record := range records[1:] {
 		// convert grade distribution from string to int
-		intSlice := [14]int{}
-
-		for j := 0; j < 13; j++ {
-			intSlice[j], _ = strconv.Atoi(record[aPlusCol+j])
-		}
-		// add w number to the grade_distribution slice
-		if wCol != -1 {
-			intSlice[13], _ = strconv.Atoi(record[wCol])
+		intSlice := make([]int, len(grades))
+		for i, col := range grades {
+			if pos, ok := indexMap[col]; ok {
+				intSlice[i], _ = strconv.Atoi(record[pos])
+			}
 		}
 
 		// add new grade distribution to map, keyed by SUBJECT + NUMBER + SECTION