def get_list_similarity_score(list1, list2):
    """
    Compare two lists and calculate a similarity score between the two lists.
    returns the number of first few identical elements between the two lists.
    """
    length = len(list1)
    if len(list2) < length:
        length = len(list2)
    score = 0
    for i in range(length):
        if list1[i] == list2[i]:
            score +=1
        else:
            break
    return score