Why is Competitor Sales a Positive Contribution?

[nknauer]

Project Robyn

Describe issue

I am running the demo and see that in the response decomposition waterfall by predictor, competitor sales is the largest contribution. Why would competitor sales be the largest contribution, shouldn't it be negative?

Provide reproducible example

This is the input directly from the demo:
InputCollect <- robyn_inputs(
dt_input = dt_simulated_weekly,
dt_holidays = dt_prophet_holidays,
date_var = "DATE", # date format must be "2020-01-01"
dep_var = "revenue", # there should be only one dependent variable
dep_var_type = "revenue", # "revenue" (ROI) or "conversion" (CPA)
prophet_vars = c("trend", "season", "holiday"), # "trend","season", "weekday" & "holiday"
prophet_country = "DE", # input country code. Check: dt_prophet_holidays
context_vars = c("competitor_sales_B", "events"), # e.g. competitors, discount, unemployment etc
paid_media_spends = c("tv_S", "ooh_S", "print_S", "facebook_S", "search_S"), # mandatory input
paid_media_vars = c("tv_S", "ooh_S", "print_S", "facebook_I", "search_clicks_P"), # mandatory.
organic_vars = "newsletter", # marketing activity without media spend
window_start = "2016-01-01",
window_end = "2018-12-31",
adstock = "geometric" # geometric, weibull_cdf or weibull_pdf.
)
print(InputCollect)

[Borghis]

I also have some variables like inflation rate and interest rate that logically have negative effect on the response, but in this case I think that the sign is based on the sign of the correlation that the variable has with the response.

[jammalz]

Probably this indicates that when competitors sell more, your company sells more too. This might be due to seasonality or trends in the market, for example.