A CRJ700 CREW WAS GIVEN AN INCORRECT BAGGAGE COUNT FOR THE FLT WT AND BAL CALCULATIONS.

Narrative

AFTER ALL PAX WERE LOADED (69); THE GATE AGENT ENTERED THE FLT DECK AND STATED '69 PAX; 5 BAGS FORWARD; 66 BAGS IN THE AFT CARGO COMPARTMENT.' THE FO RECORDED THIS INFO AND BEGAN COMPUTING WT AND BAL DATA. AT THAT TIME; I WAS BUSY DEALING WITH AN EXTREMELY DISRUPTIVE CHILD. THE ISSUE WITH THE CHILD WAS RESOLVED AND THE FO COMPLETED THE PAPERWORK. I REVIEWED IT AND PASSED IT OUT THE DOOR. WE CLOSED THE MAIN CABIN DOOR. AS SOON AS THE FORWARD AND AFT CARGO DOORS CLOSED; WE RAN THE STARTING ENGS CHKLIST. THE GND CREW PUSHED US BACK AND WE TAXIED TO THE RWY. DURING THE TKOF ROLL; OPS ATTEMPTED CONTACT ON COM #2. AT A SAFE ALT I CALLED THEM BACK AND WAS INFORMED THAT 22 CHKED BAGS HAD NOT BEEN LOADED. OPS THEN INFORMED ME THAT OUR CORRECT BAG COUNT WAS NOT 44 AFT INSTEAD OF 66. OUR PERFORMANCE/WT AND BAL COMPUTATIONS WERE BASED ON 66 BAGS AFT; WHICH IS WHAT WE WERE TOLD PRIOR TO PUSHBACK. IN OTHER WORDS OPS GAVE US A BAG COUNT PRIOR TO ACTUALLY LOADING THE BAGS. THEY ALSO SECURED THE CARGO COMPARTMENT AND MISTAKENLY LEFT 22 BAGS ON A CART IN FRONT OF OPS. FINALLY; THEY PUSHED US BACK AND SALUTED WITHOUT REALIZING THAT ALL THE BAGS HAD NOT BEEN LOADED. THIS WAS A DIFFERENCE OF 671 LBS AND .8 INDEX FORWARD. HAD WE BEEN CLOSE TO PERFORMANCE OR WT AND BAL LIMITS; THIS COULD HAVE DEVELOPED INTO AN EXTREMELY DANGEROUS AND CATASTROPHIC SIT.