Collect and prepare sequences
Aggregate ordered user events (clicks, views, purchases) into sessions and apply time-windowing and de-duplication before train/test splitting.
Predict next item in a sequence. Balance relevance and novelty.
Sequential recommendation predicts which item a user is likely to interact with next by using the order and context of past interactions. Important practical issues include session boundaries, recency weighting, cold-start users and evaluating next-item accuracy with top-K metrics such as Precision@K and NDCG.
Learning concept · Not a validated service
Sequential recommendation predicts which item a user is likely to interact with next by using the order and context of past interactions. Important practical issues include session boundaries, recency weighting, cold-start users and evaluating next-item accuracy with top-K metrics such as Precision@K and NDCG.
A proposed application: short-session next-item suggestions for an e-commerce browse funnel that help users resume shopping. This starter does not implement time or session-aware models and would need extension before deployment.
Aggregate ordered user events (clicks, views, purchases) into sessions and apply time-windowing and de-duplication before train/test splitting.
Start with simple next-item baselines (Markov chain, item co-occurrence) then compare to sequence-aware models (RNNs, Transformer or SASRec).
Use top-K metrics such as Precision@K, Recall@K and NDCG for next-item prediction and inspect error cases by session length and recency.
Serve ranked candidates with fallbacks for cold-starts, log online impressions for A/B testing and monitor drift in item catalogue and behaviour.
The supplied starter builds a tiny user-item ratings table from hand-written rows, computes cosine similarity between user vectors, finds the most similar user to a target, and recommends that neighbour's unseen items. It implements a basic user-based collaborative filter on static ratings but does not use any sequential or time-ordered interaction signals named in the title.
matrix = ratings.pivot_table(index="user", columns="item", values="rating").fillna(0)
user_similarity = pd.DataFrame(
cosine_similarity(matrix),
index=matrix.index,
columns=matrix.index,
)
target_user = "user_1"
neighbor = user_similarity[target_user].drop(target_user).idxmax()
unseen_items = matrix.loc[target_user][matrix.loc[target_user] == 0].index
scores = matrix.loc[neighbor, unseen_items].sort_values(ascending=False)The code contains no sequence or time information: it treats ratings as a static matrix and uses user-based similarity. It uses a tiny synthetic ratings table (12 rows) rather than ordered event sequences, so it cannot validate next-item prediction or session-aware behaviour.
Proposed extension: build a next-item pilot that uses ordered click events and recency weighting. Compare a simple co-occurrence/Markov baseline with a session-aware model (e.g. SASRec) and measure Precision@10 and NDCG@10 on held-out sessions.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.