Count, LT, PH, PT Column in Functional Annotation Chart

Hello nhaus,
The explanation part has been given in the "Help and tool manual" that's there on the right top of the annotation summary result page or you can check in the following DAVID link.

david.ncifcrf.gov/helps/functional_annotation.html#summary

The following explanation has been given, based on the instructions from the above DAVID link. Consider the following result from a chart record.

Eg: Category Term Count % PValue Genes List Total
GAD_DISEASE metabolic syndrome 6 16.66666667 5.58E-05 HSD11B1, FADS2, ADIPOQ, APOE, F3, PPARGC1A 34

Pop Hits Pop Total Fold Enrichment Bonferroni Benjamini FDR
165 12971 13.87272727 0.058244592 0.034299056 0.034044044

Category - Every term in the annotation cluster

Count - Genes involved in individual terms.
The count column in the result chart denotes the number of involved genes (from the input list of genes) that has been annotated to that specific term. Here the count is 6. This means, out of 36 total genes (from my list), 6 genes are involved and got annotated to "Metabolic syndrome" term.

% = (Involved genes / Total genes) * 100
Eg: Involved genes = 6 (value under count)
Eg: Total genes = 36 (From my study)
% = (6/36) * 100 = 16.66666667 (This value has been displayed under % column). Using the % formula, one can check the values under % column of the chart.

P-Value = EASE Score, the modified Fisher Exact P-Value. They are identical to that in the Chart Report. The smaller, the more enriched.
The p-values associated with each annotation terms inside each clusters are exactly the same values as p-values (Fisher Exact/EASE Score) shown in the regular chart report for the same terms.

Genes = Official gene symbol of the involved genes. The number that's been given under "Count" column will match to this displayed "Genes" column. Say, Count 6 denotes those 6 genes are annotated to that specific term "Metabolic syndrome" and their names (6 genes) are displayed under Genes column.

Gerenal definition :
Population Total (PT) = Total genes in the human genome background.
Population Hits (PH) = Total number of genes involved in the specific pathway / database.
List Total (LT) = Total genes in the gene list (User's input gene list).
List Hits (LH) = Total number of genes from the gene list (User's input gene list) involved in the specific pathway / database.

From the example table,
List Total (LT) = 34 (Value under List Total)
Population Hits (PH) = 165 (Value under Pop Hits)
Population Total (PT) = 12971 (Value under Pop Total)
List Hits (LH) = 6 (Value under Count)

In the "Homo sapiens" as background (12,971 genes total; Population Total (PT)), 165 genes are involved in the Metabolic syndrome (Population Hits (PH)). A given gene list has found that Six genes (List Hits (LH)) out of 34 total genes in the list (List Total (LT)) belong to the Metabolic syndrome. Then we ask the question if 6/34 is more than random chance compared to the "Homo sapiens" background of 165/12971.

DAVID tool is used when our gene list has "Differentially Expressed Genes" (DEGs). The tool enriches the statistically significant DEGs and displays the results as chart based on modified Fisher Exact p values. The smaller the p values, the more those genes are enriched - statistically significant.

Hope, the explanation helps.
Regards,
Subhashini.