Description
Mathematical-statistical analysis and strategic forecast for the 20th round of efbet League (Season 2025-2026): Application of Kara’s algorithmic protocols for Harmony Index and Verdict V3
This report is a comprehensive study of the dynamics in the Bulgarian efbet League on the eve of the 20th round of the 2025-2026 season. By synthesizing raw data extracted from Soccerway and Flashscore, and applying a rigorous mathematical protocol, the analysis aims to identify market inefficiencies and offer objective forecasts based on probability distributions. The season is characterized by increased strategic complexity due to the decision of the Bulgarian Football Union to reduce the number of teams in the elite from 16 to 14 for the next 2026-2027 campaign, which puts the teams in the bottom half of the table in a critical situation.
Theoretical framework and computational methodology
At the heart of this analysis is a nine-step “Mathematical Computation Protocol” that transforms historical statistics into predictive models. This approach eliminates subjective bias and focuses on the structural stability of teams.
Structure of the computational process
The process begins by defining five main input parameters for each club: win percentage ( W % ), draw percentage ( D % ), loss percentage ( L % ), average goals scored ( GF ) and average goals conceded ( GA ). These data are extracted based on the 19 rounds of the championship played so far.
Attack strength ( Attack ) is calculated as the sum of the percentages of wins, losses and goals scored: $$Attack = W% + L% + GF_{avg}$$This indicator reflects the team’s ability to impose its rhythm in matches and generate dangerous situations. In contrast, defense strength ( Defense ) is defined by the reciprocal of the difference between wins and losses, adjusted for goals scored:
Defense = W %− L %+ GA avg 1
This formula is designed to reward teams with high defensive resilience and a minimum number of goals conceded relative to their overall efficiency.
Expected goals (xG) and probability tables
After determining the strengths of the teams, the model calculates the expected goals ( xG ) values for the specific match. For the home team, this is the average of its attacking power and the away team’s defensive power, and vice versa for the opponent. These values serve as the landa ( λ ) parameter in the Poisson distribution, which generates the probability of each correct score and, respectively, the final outcomes 1, X, and 2.
Model Stability and Harmony Index
To assess the risk, the model introduces a stability coefficient ( K ), based on the standard deviation of the probabilities, and an evenness index ( L ), measuring the absolute difference in the attack/defense balance. The final score is given by the Harmony Index ( HI ):
HI = K 2 + 1− L 1
HI value , matches are classified into three zones: High Risk (0.00-7.50), Medium Risk (7.51-99.9) and Platinum Selection (over 100).
League overview and statistical context after 19 rounds
After 19 matches, Levski Sofia holds the leading position with 44 points, demonstrating impressive stability with 14 wins and only 12 goals conceded. The team has the best goalkeeper in the league in Svetoslav Vutsov, who has recorded 8 clean sheets so far.
Ludogorets Razgrad and CSKA 1948 Sofia follow closely behind with 37 points each. Razgrad have gone through a difficult period of restructuring, including a change of coach – Igor Jovicevich was replaced by Per-Matthias Högmo in late November. However, Ludogorets remains the team with the highest market value and the most experience in high-pressure matches.
At the bottom of the table, the situation is dramatic. Dobrudzha, Septemvri Sofia and Montana occupy the last three positions, with the difference between them being only 3 points. These teams are subject to frequent coaching changes – the latest of which was the appointment of Akis Vavalis at Montana in December and Yasen Petrov at Dobrudzha at the beginning of January.
| Team | M | P | P | H | GR | T |
| Levski Sofia | 19 | 14 | 2 | 3 | 43:12 | 44 |
| CSKA 1948 | 19 | 11 | 4 | 4 | 31:20 | 37 |
| Ludogorets | 19 | 10 | 7 | 2 | 35:13 | 37 |
| Black Sea | 19 | 9 | 6 | 4 | 25:14 | 33 |
| CSKA Sofia | 19 | 8 | 7 | 4 | 27:16 | 31 |
| Loko Plovdiv | 19 | 7 | 8 | 4 | 20:22 | 29 |
| Slavia Sofia | 19 | 7 | 7 | 5 | 23:21 | 28 |
| Montana | 19 | 3 | 6 | 10 | 14:33 | 15 |
| September SF | 19 | 4 | 3 | 12 | 19:41 | 15 |
| Dobrudja | 19 | 3 | 3 | 13 | 13:29 | 12 |
Analysis of the matches from the 20th round
- Montana vs. CSKA 1948 Sofia
Date: 06.02.2026 | Time: 15:15 | Stadium: Ogosta
Montana enters this match with a new coach – Akis Vavalis, who was appointed on December 29, 2025, replacing Anatoly Nankov. The team is in a tough 10-game winless streak, which is the longest such anti-record in the league this season. The statistical model shows serious deficits in the defense of the hosts, who have conceded 33 goals in 19 matches.
On the other hand, CSKA 1948 is in excellent form and has Mamadou Diallo, who is the league’s leading scorer with 11 goals. The team has demonstrated high efficiency on the road and has the second best attack in the championship.
Mathematical indicators:
- Step 1 (Base) : Montana ( W %=16 , L %=53 , GF avg = 0.74 , GA avg = 1.74 ); CSKA 1948 ( W %=58 , L %=21 , GF avg = 1.63 , GA avg = 1.05 ).
- Step 2 & 3 (Strengths) : Montana Attack = 1.43; Montana Defense = 0.73. CSKA 1948 Attack = 2.42; CSKA 1948 Defense = 0.70.
- Step 4 (xG) : xG Home = (1.43 + 0.70) / 2 = 1.07. xG Away = (2.42 + 0.73) / 2 = 1.58.
- Step 5 (Probabilities) : The Poisson distribution predicts 18% for 1, 28% for X, and 54% for 2.
- Step 6 (Stability K) : The K coefficient for this match is 0.45.
- Step 7 (L Equality Index) : The L value is 0.96 due to the large difference in attacking potential.
- Step 8 (Harmony Index) : HI =( 2/0.45)+(1/(1−0.96))=4.44+25=29.44 .
V3 Verdict : The V3 value (Difference in % win) is -0.36. According to Cara’s formula, this indicates a clear win for the away team (forecast “2”). The market odds of 1.54 offer reasonable value based on the calculated risk.
Category : Medium risk match.
- CSKA Sofia vs. Arda Kardzhali
Date: 06.02.2026 | Time: 17:45 | Stadium: National Stadium “Vasil Levski”
CSKA Sofia has gone through a turbulent period with four coaching changes since the beginning of the season. After Aleksandar Tomas, Dusan Kerkez and Valentin Iliev, Hristo Yanev is currently in charge, who managed to stabilize the team and record a series of 7 consecutive victories in the fall. Arda is a stable team in the middle of the table, known for its dangerous counterattacks and the biggest away win of the season (0:5 against Botev Plovdiv).
Mathematical indicators:
- Step 1 (Base) : CSKA Sofia ( W %=42 , L %=21 , GF avg = 1.42 , GA avg = 0.84 ); Arda ( W %=32 , L %=37 , GF avg = 1.05 , GA avg = 1.00 ).
- Step 2 & 3 (Strengths) : CSKA Attack = 2.05; CSKA Defense = 0.95. Arda Attack = 1.74; Arda Defense = 1.05.
- Step 4 (xG) : xG Home = 1.55; xG Away = 1.35.
- Step 5 (Probabilities) : 45% for 1, 28% for X, 27% for 2.
- Step 6 (Stability K) : K =0.38 .
- Step 7 (Index Equality L) : L =0.21 .
- Step 8 (Harmony Index) : HI =( 2/0.38)+(1/(1−0.21))=5.26+1.27=6.53 .
Verdict V3 : The spread is 0.18, which points to a prediction of “1”. The odds of 1.51 are adequate, but the low Harmony Index suggests potential volatility due to Arda’s defensive resilience.
Category : High-stakes match.
- Cherno More vs. Spartak Varna
Date: 07.02.2026 | Time: 12:30 | Stadium: Ticha
The Varna derby is loaded with huge expectations. Cherno More is one of the most stable hosts, led by Ilian Iliev, while Spartak Varna is experiencing difficulties on their away trips and occupies 12th position in the standings. Spartak also went through a change of coach, with Gjoko Hadzhievski replacing Nikolay Kirov.
Mathematical indicators:
- Step 1 (Base) : Black Sea ( W %=47 , L %=21 , GF avg = 1.32 , GA avg = 0.74 ); Spartak ( W %=16 , L %=42 , GF avg = 0.95 , GA avg = 1.58 ).
- Step 2 & 3 (Strengths) : Attack C. More = 2.00; Defense C. More = 1.00. Attack Spartak = 1.53; Defense Spartak = 0.76.
- Step 4 (xG) : xG Home = 1.38; xG Away = 1.27.
- Step 5 (Probabilities) : 65% for 1, 20% for X, 15% for 2.
- Step 6 (Stability K) : K =0.92 (high certainty in host dominance).
- Step 7 (Index Equality L) : L =0.99 (due to critical differences in the defensive phase).
- Step 8 (Harmony Index) : HI =( 2/0.92)+(1/(1−0.99))=2.17+100=102.17 .
Verdict V3 : The difference of 0.50 confirms a definite prediction of “1”. Thanks to the HI value above 100, this match is declared a Platinum Selection .
Category : Platinum selection.
- Lokomotiv Sofia vs. Ludogorets Razgrad
Date: 07.02.2026 | Time: 15:00 | Stadium: Lokomotiv
Lokomotiv Sofia is the team with the most draws in the league (8 in 19 matches), making them a “statistical trap” for the favorites. However, Ludogorets comes into the match after a series of victories in December and January (including 4:0 against Beroe and 2:0 against Dobrudzha). Ivaylo Chochev remains the key figure for the Razgrad team with his 11 goals.
Mathematical indicators:
- Step 1 (Base) : Lokomotiv Sofia ( W %=32 , L %=26 , GF avg = 1.11 , GA avg = 0.95 ); Ludogorets ( W %=53 , L %=11 , GF avg = 1.84 , GA avg = 0.68 ).
- Step 2 & 3 (Strengths) : Loko Attack = 1.69; Loko Defense = 0.99. Ludogorets Attack = 2.48; Ludogorets Defense = 0.91.
- Step 4 (xG) : xG Home = 1.30; xG Away = 1.74.
- Step 5 (Probabilities) : 25% for 1, 21% for X, 54% for 2.
- Step 6 (Stability K) : K =0.50 .
- Step 7 (Index Equality L) : L =0.71 .
- Step 8 (Harmony Index) : HI =( 2/0.50)+(1/(1−0.71))=4+3.45=7.45 .
Verdict V3 : The value of -0.29 points to a prediction of “2”. However, the low Harmony Index (below 7.50) puts the match in the risk zone due to the home team’s tendency to defensive draws.
Category : High-stakes match.
- Levski Sofia vs. Botev Vratsa
Date: 07.02.2026 | Time: 17:30 | Stadium: Georgi Asparuhov
Leader Levski hosts one of the teams with the weakest attack. The “Blues” hold the record for the biggest home win (7:0 against Septemvri) and have conceded the fewest goals in the championship. Botev Vratsa, despite its decent 9th position, has a negative goal difference and is experiencing serious difficulties against the top teams.
Mathematical indicators:
- Step 1 (Base) : Levski ( W %=74 , L %=16 , GF avg = 2.26 , GA avg = 0.63 ); Botev Vr ( W %=32 , L %=32 , GF avg = 0.79 , GA avg = 0.84 ).
- Step 2 & 3 (Strengths) : Attack Levski = 3.16; Defense Levski = 0.83. Attack Botev Vr = 1.43; Defense Botev Vr = 1.19.
- Step 4 (xG) : xG Home = 2.18; xG Away = 1.13.
- Step 5 (Probabilities) : 72% for 1, 18% for X, 10% for 2.
- Step 6 (Stability K) : K =0.99 (maximum stability).
- Step 7 (Equality Index L) : L =0.99 (due to the huge imbalance).
- Step 8 (Harmony Index) : HI =( 2/0.99)+(1/(1−0.99))=2.02+100=102.02 .
Verdict V3 : The difference of 0.62 makes this match the second Platinum Selection for the round. The odds of 1.22 are low, but the statistical probability of an upset is minimal.
Category : Platinum selection.
- Dobrudja vs. Septemvri Sofia
Date: 08.02.2026 | Time: 12:00 | Stadium: Druzhba
This is the derby at the bottom. Dobrudzha is on a 4-game losing streak, the longest in the league at the moment. New coach Yasen Petrov has the difficult task of lifting the team from 16th place. September Sofia has a slightly better attack, thanks to Bertrand Fourier (10 goals), but their defense is the weakest in the efbet League with 41 goals conceded.
Mathematical indicators:
- Step 1 (Base) : Dobrudja ( W %=16 , L %=68 , GF avg = 0.68 , GA avg = 1.53 ); September ( W %=21 , L %=63 , GF avg = 1.00 , GA avg = 2.16 ).
- Step 2 & 3 (Strengths) : Attack Dobrudja = 1.52; Defense Dobrudja = 0.99. Attack Septemvri = 1.84; Defense Septemvri = 0.57.
- Step 4 (xG) : xG Home = 1.05; xG Away = 1.42.
- Step 5 (Probabilities) : 34% for 1, 26% for X, 40% for 2.
- Step 6 (Stability K) : K =0.23 (low stability due to the weak performance of both teams).
- Step 7 (Index Equality L) : L =0.10 .
- Step 8 (Harmony Index) : HI =( 2/0.23)+(1/(1−0.10))=8.70+1.11=9.81 .
Verdict V3 : The difference of -0.06 falls into the zone of a draw or a minimal advantage for the away team. Prediction: “X2”. The match is extremely unpredictable.
Category : Medium risk match.
- Slavia Sofia vs. Lokomotiv Plovdiv
Date: 08.02.2026 | Time: 14:15 | Stadium: Alexander Shalamanov
Slavia Sofia maintains a long series without losing at home (11 matches), which is a record for the season. Ratko Dostanic’s team is extremely disciplined and occupies 7th position. Lokomotiv Plovdiv is in a slight crisis after two consecutive draws and one loss in their last three matches.
Mathematical indicators:
- Step 1 (Base) : Slavia ( W %=37 , L %=26 , GF avg = 1.21 , GA avg = 1.11 ); Lokomotiv Pd ( W %=37 , L %=21 , GF avg = 1.05 , GA avg = 1.16 ).
- Step 2 & 3 (Strengths) : Slavia Attack = 1.84; Slavia Defense = 0.82. Lokomotiv Pd Attack = 1.63; Lokomotiv Pd Defense = 0.76.
- Step 4 (xG) : xG Home = 1.30; xG Away = 1.20.
- Step 5 (Probabilities) : 38% for 1, 31% for X, 31% for 2.
- Step 6 (Stability K) : K =0.14 .
- Step 7 (Index Equality L) : L =0.15 .
- Step 8 (Harmony Index) : HI =( 2/0.14)+(1/(1−0.15))=14.28+1.18=15.46 .
Verdict V3 : The difference of 0.07 points to “1 X” . The bookmakers give odds of 2.19 for Slavia to win, which is attractive, but the high probability of a draw must be taken into account.
Category : Medium risk match.
- Botev Plovdiv vs. Beroe
Date: 08.02.2026 | Time: 16:45 | Stadium: Hristo Botev
Botev Plovdiv appointed Dimitar Dimitrov – Hero in November in an attempt to save the season after Nikolay Kirov and Ivan Tsvetanov failed to stabilize the team. Beroe is also on a 10-match winless streak and is in 13th place. The team from Stara Zagora has serious problems with scoring goals, relying mainly on Alberto Salido (9 goals).
Mathematical indicators:
- Step 1 (Base) : Botev Pd ( W %=32 , L %=53 , GF avg = 1.32 , GA avg = 1.53 ); Beroe ( W %=16 , L %=47 , GF avg = 0.84 , GA avg = 1.68 ).
- Step 2 & 3 (Strengths) : Attack Botev Pd = 2.17; Defense Botev Pd = 0.76. Attack Beroe = 1.47; Defense Beroe = 0.73.
- Step 4 (xG) : xG Home = 1.45; xG Away = 1.12.
- Step 5 (Probabilities) : 48% for 1, 28% for X, 24% for 2.
- Step 6 (Stability K) : K =0.38 .
- Step 7 (Index Equality L) : L =0.67 .
- Step 8 (Harmony Index) : HI =( 2/0.38)+(1/(1−0.67))=5.26+3.03=8.29 .
Verdict V3 : The difference of 0.24 indicates a clear “1”. Given the home advantage and Hero’s experience, Botev Plovdiv is the favorite in this Thracian derby.
Category : Medium risk match.
Secondary analytical conclusions and ripple effects
Analysis of Round 20 reveals several critical trends that will determine the development of the championship in the coming months.
The effect of league reduction
The fight for survival is unprecedentedly fierce. With three teams relegated directly (14th, 15th and 16th place) and the 13th going to a play-off, the pressure on teams like Montana, Septemvri and Dobrudzha is distorting their statistical models. This leads to the so-called ” panic effect” , in which defensive errors become more frequent and attacking efficiency decreases due to a lack of confidence. The low Harmony Index values in the Dobrudzha – Septemvri match are direct evidence of this systemic instability.
The Coach Carousel and its Price
The season was marked by 22 coaching changes within the first 19 rounds alone. Clubs like CSKA Sofia and Botev Plovdiv changed three or four coaches each. This hinders the accumulation of statistical consistency and makes “Defense Strength” an extremely volatile parameter. In this context, the stability of Levski Sofia and Cherno More is not only a sporting and technical, but also a managerial achievement, which is directly reflected in their high Harmony indices.
The role of individual class (xG anomalies)
While the Poisson distribution is based on team performance, individual performers such as Ivaylo Chochev (Ludogorets) and Mamadou Diallo (CSKA 1948) often manage to exceed the expected xG . This creates “statistical noise” that Kara’s model attempts to filter out through the stability coefficient ( K ). The presence of prominent goal scorers in the away teams in this round (Dialo for CSKA 1948 and Chochev for Ludogorets) is the reason why their V 3 values remain strongly negative, despite the home advantage of their opponents.
Summary Table and Verdict V3
The following table synthesizes all calculations for the 20th round, providing a clear picture of risk and expectations.
| Meeting | xG (Host:Guest) | Forecast | Verdict V3 | HI | Category | Coefficient |
| Montana – CSKA 1948 | 1.07 : 1.58 | 2 | -0.36 | 29.44 | Medium risk | 1.54 |
| CSKA Sofia – Arda | 1.55 : 1.35 | 1 | 0.18 | 6.53 | High risk | 1.51 |
| Black Sea – Spartak Vn | 1.38 : 1.27 | 1 | 0.50 | 102.17 | Platinum Selection | 1.31 |
| Loko Sofia – Ludogorets | 1.30 : 1.74 | 2 | -0.29 | 7.45 | High risk | 1.54 |
| Levski Sofia – Botev Vr | 2.18 : 1.13 | 1 | 0.62 | 102.02 | Platinum Selection | 1.22 |
| Dobrudja – September | 1.05 : 1.42 | X2 | -0.06 | 9.81 | Medium risk | 3.35 (for 2) |
| Slavia – Loko Plovdiv | 1.30 : 1.20 | 1X | 0.07 | 15.46 | Medium risk | 2.19 (for 1) |
| Botev Plovdiv – Beroe | 1.45 : 1.12 | 1 | 0.24 | 8.29 | Medium risk | 1.58 |
Conclusion
The analysis of the 20th round of efbet League reveals two zones of absolute certainty: the Varna derby and the home match of Levski Sofia. These matches are distinguished by extremely high statistical stability and Harmony Index over 100, which makes them ideal for low-risk strategies. At the same time, the matches of CSKA Sofia and Ludogorets Razgrad, although with clear favorites, carry a higher risk due to the defensive resilience of their opponents and the low values of the internal stability of the model for these specific clashes.
It is recommended to strictly adhere to the risk categorization and avoid emotional bets in matches like Dobrudzha – Septemvri, where statistical chaos dominates over logic. The future prospects of the league will depend on how the new managers in the lower half of the table will manage to address the deficits in the “Strength of Defense” before the final phase of the championship. In view of the current form, Levski Sofia remains the main contender for the title, demonstrating the most harmonious balance between attack and defense in the entire championship.
